science of the sea - forgotten books
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SCIENCE OF THE SEA
AN ELEMENTARY HANDBOOK OF PRACTICAL
OCEANOGRAPHY FOR TRAVELLERS,
SAILORS, AND YACHTSMEN
PREPARED BY
THE CHALLENGER SOCIETYFOR THE PROMOTION OF THE STUDY OF OCEANOGRAPHY
EDITED BY G . HERBERT FOWLER,B .A .
,PH.D . ,
ETC .
SOMETIME ASSISTANT PROFESSOR OF ZOOLOGYUNIVERSITY COLLEGE , LONDON
WITH ILLUSTRATIONS AND CHARTS
LONDONJOHN MURRAY ,
ALBEMARLE STREET,w .
1 9 12
FIG. 1 .
CHALLENGER , 1 8 7 3- 1 876 .
PREFACE
NOT seldom those who are engaged in oceanographicwork are asked by someone about to start on a longvoyage : How can I do some work for science ? Idon ’ t know anything about it ; where can I read itup P Such seekers after knowledge might often domost valuable work ,
even in waters which they wouldexpect to be quite well known . In this study yachtsmen
,and ofiicers of the Royal Navy , who are apt to
find time heavy on their hands in port or on a foreignstation
,could enj oy an ever- fresh interest in the sea ,
its workings,and its inhabitants even officers of the
Merchant Service could find time to help , especiallyin meteorological and surface-water work . To all such
vi PREFACE
this handbook is primarily addressed : to those whoare willing to take Observations , but fear that a lackof scientific training will render their work or theircollections worthless . Anyone who follows the lineshere laid down m ay feel certain that his work will havereal value
,that he is building a sound brick into the
pyramid of human knowledge . In order still furtherto promote the work
,the Challenger Society has named
an advisory committee of specialists in various branchesof oceanography , to whom may be referred throughthe Honorary Secretary inquiries upon points whichare beyond the elementary scope of the handbook .
But all who propose to take observations,in whatever
branch,are strongly advised to spend a few days at
one of the marine stations (pp . 423 in orderthoroughly to understand the practical work .
However valuable the information in this handbookmay prove to be
,it must remain elementary. It is no
royal road in no sense will it do away with theserious study which all those must undergo who , notcontent merely to record observations
,wish also to
grasp the usefulness and meaning of what they aredoing . But the book m ay fairly claim to have broughtbetween two covers instructions
,of which many are
not in print , and the rest are scattered and hard tofind .
The indiscriminate use by the writers o f Fahrenheitand Centigrade , metres and fathoms , will prepare thereader for what he will find in the literature of thesubj ect an oceanographer must be able to think ineither scale .
The selected list of manufacturers and tradesmen
(p . 438) should prove of value to the beginner .
The obj ect of the volume is severely practical—whatto do , and how to do it—written in language which ,
PREFACE Vfi
as far as possible,takes no previous scientific training
for granted . The headings of the various chapterssufficiently explain the general plan . With a singleexception
,they have been written by Fellows of the
Society ; to the exception—Mrs . Dr .A .Weber van Bosse ,the wife of an Honorary Fellow, and herself distin
guished for researches on Algae—the Society desires toexpress its Special indebtedness . To those who haveallowed the use of existing illustrations (notably toSir John Murray, who placed the blocks of the Reportsof H .M.S . Challenger at our disposal ; and to Mr . S .
Henshaw , Curator of the Museum of ComparativeZoology at Cambridge , Mass , who allowed the use ofblocks from Three Cruises of the as alsoto numerous manufacturers who have freely suppliedvaluable information
,the Society also renders its
thanks .
The first edition of such a work as this is necessarilyof a tentative nature , and the Editor will gratefullyreceive corrections and suggestions of all kinds for afuture issue .
G . HERB ERT FOWLER .
AS PLE Y GU ISE ,
B EDFORD SH IRE ,
April, 1 9 1 2 .
INTRODUCT ION
BY THE ED ITOR
ALTHOUGH the general arrangement of land and waterat the surface of the earth
,as shown in ordinary maps ,
is familiar to every schoolboy , yet nowadays , when theuse of the globe as an instrument for teaching is somewhat out of fashion
,not only the importance
,but even
the very shape of the water is apt to be overlooked—a
neglect fostered by atlases which,as a rule
,are con
cerned merely with the land . Yet the surface of theearth shows about two and a half times as much wateras land . Again , the ordinary atlas fails to Show thatthe land is massed towards the North Pole
,the water
towards the South . It is possible to draw a greatcircle
,the hemisphere north of which (Fig . 3 ) shows
land and water in about equal proportion s (47 :but in its southern hemisphere (Fig . 2) nine- tenths ofthe surface is under water . Still less do ordinary mapsdisplay the connection between the great ocean stheir South passes into a blank Unknown . It is noteasy to get a proper grasp of this connection exceptfrom a globe but several of the star proj ections (Fig . 4)Show fairly well that the three great oceans—Pacific ,
Atlantic , and Indian—can be regarded as bays of thatsingle Southern Ocean which forms a not very wide beltround the Antarctic Continent , narrowed to about540 sea miles between the latter and the Horn .
These three great bays have certain features inCommon in the Pacific , owin g to the scattered islands ,
1X
FIG . 2 . FIG . 3 .
FIG . 4 .
FIG . 2 .—OCEANIC OR WATER HEM ISPHERE .FIG . 3 .—CONTINENTAL OR LAND HEM I SPHERE .FIG . 4 ,—THE SOUTH POLE ON THE
“ STAR PROJECTION OFSTE INHAU S .(Figs . 2 and 3 from Huxley ’s Physiography Fig. 4 from
el’
s Handbuch d er Ozeanographie ,by p erm ission o f
Messrs?”
Macm illan . and J . Engelhorn’
s Verlag in Stuttgartresp ectively . )
INTRODUCTION
FIG . 5 .
xi
xii INTRODUCTIONsome of them are less well marked than in the almostislandless Atlantic the Indian , representin g , as itwere
,the southern half of the other two , shows them
more clearly during the south-west monsoon thanduring that from the north- east but they are recogn isable in all . The diagram in Fig . 5 gives a roughidea of these resemblances between the three greato ceanic areas , in air pressures , In WlndS , and in currents the latitudes of corresponding regions , however ,vary somewhat in the different areas .
In these phenomena of pressure , wind, and currentthe sun is the source of energy . It may be said , in themost general terms , that the distribution of marineanimals and plants depends mainly on water temperatures , the water temperatures almost entirely ono ceanic currents
,the currents chiefly on prevailing
winds,the winds on barometric pressures
,and the
pressures on the effects of the sun’s rays upon Earth,
Air , and Water . It is easy to make a general statem ent of this kind it is not so easy to prove every linkin the chain and , until we have accumulated far moreknowledge than at present we possess
,some parts of
it must be of the nature of Articles of Faith and,like
most such Articles , they have their sceptics . St ill lessdo we know of the details of the inner working of thoses tupendous phenomena which affect five- sevenths o f theEarth ’s surface .
At the other end of the scale—so far as mere size isconcerned—we do not at present really understandthe life of a single rock-pool
,the delicate adjustment
which exists between the myriads of organisms,its
inhabitants . We recognize dimly the outlines of themain processes—the unending cycle in which foodm aterial passes from plant to animal
,and 'back to plant
again ; the struggle for existence—as keen amongst
INTRODUCTIONthe microscopic tenants of a rock-pool as among thelarger animals of a more obvious world and so forth .
But we are unable to isolate mentally a single species ,and to describe how it reacts to the incessant changesof its physical and organic environment .
Between these extremes of scale—between thegigantic and world- embracing movements of Air andWater
,and the brief life of the minutest organism
lie , intricately interwoven ,the problems with which the
student of oceanography must wrestle . But while hisproper work is the orderly marshalling of facts intogroups
,as a basis for explanations—or at least for
hypotheses—the facts themselves can be gathered inquantity by any traveller who chooses to take thetrouble of doing so .
CONTENTS
CHAPTER PAGE S
PREFACE AND INTROD UCT ION v—xii iB y the ED ITOR .
ADDE ND A xviiL I ST OF CHA RT S xviii
I . THE A IR
B y H . R . MILL, D .Sc LL .D D irector of the B ritishRain fall A ssociation ; and D . WILSON BARKER.R .N .R Cap tain Sup erin tenden t of the
Nautical Train ing College . H .M .S . Worcester .
I I . THE WA TE RB y H . N .
fi
D ICK SON , M .A D .Sc Professor of Geography in Un iversity College , Reading and D . J . MATTHEWS , Hydrographer to the Marin e B iologicalAssociation and to the B oard o f Agriculture for
Ireland (Fisheries B ran ch ) ; with an OUTLINE OF
OCEANIC CIRCULATION by the ED ITOR .I I I . THE SHOR E
A .
B .
C .
T ROP I CA L SHORE COLLE CT INGCORAL REE FS AND I SLAND SH INT S FOR T RO P I CA L OUTF I TB y J . STANLEY GARD INER , M .A Professor ofZoology in the Un iversity of Cambridge .
IV . THE PLA NT SA . FLOA T ING PLAN T SB y V . H . B LACKMAN , M .A Professor of Plan tPhysiology and Pathology, Imp erial College of
Scien ce and Techn ology.B . F IXED PLAN T SB y Mrs . A . WEBER VAN B OSSE. Ph.D .
CONTENTSCHAPTER
V .
VI .
VI I .
VI I I .
IX.
XI .
XII .
XI I I .
THE FLOAT ING AN IMALSB y the ED ITOR and EDWARD T. B ROWNE , M.A
Un iversity College , London .
THE SEA FLOOR 200
B y Sir JOHN MURRAY. K.G.B LL .D . , F .R .S .
Naturalist qr; theExp edition -of H .M.S . Challenger.1 873 -1 876.
AN IMALS OF THE SEA FLOORB y W. T; CALMAN , F .L .S F.Z .S B ritishMuseum (Natural History) ; and G . P. FARRAN . B .A . .
D epartm en t ofAgr iculture and Techn ical Instructionfor Ireland (Fisheries B ran ch ) .
Y A CHT E QU I PMEN TB y the ED ITOR and STANLEY W. KEMP. M .A
Indian Museum , Calcutta .
D RED G ING AND TRAWL INGB y E . J . ALLE N . D .Sc . . Director of the Plym outh
Laboratory. Honorary Secretary of the Marin e B iological Association and STANLEY W. KEMP .F I SHE S AND F I SH ING
B y L .
'
W. BYRNE , M .A . , B arrister-at-Law .
PR E SERVAT ION OF MA R INE ORGAN ISMSB y E . J . ALLEN , D .so and E . T. B ROWNE. M.A .
WHALE S , SEAL S , A N D SEA -SE RPENTSB y D
’ARCY WENTWORTH THOMPSON , C .B M.AProfessor of Zoology in Un iversity Co llege , Dundee .
LOGS , NOTE S,AND LAB E LS
,ETC .
B y the EDITOR.L I ST OF MA R INE STAT ION SCLA S S IF ICAT IONSL ITE RATURECLA S S IFIED L I ST OF R ECOMME NDED F IRMSINDEx
‘
ADDENDA
CHA RT I .—An Isotherm of 90
°F . has been om itted over
the North-Western p art of Au stral ia .
PAGE 29 .
D I S SOLVED SUB S TAN CE S IN PA RTS BY WE IGHT OF
SEA WA TER OF CHLOR INE CONTE N T 20 PR O M ILLE(CALCULATED FROM THE MEAN OF SEVE N TY-SEVENA NALYSE S BY D I TTMAR ) .
3 6-09 1
Ac cord ing to Knudsen ’
s tables , su ch a sea water wou ldhave a sal in ity of p ro m il le . The sl ight d ifferencebetween them is due ch iefly to im p rovem en ts in an alyticalm ethods .
PAGE 47 .
Messrs . Negretti an d Zam bra have recen tly m ade to
Mr . Matthews ’ in stru ction s two revers ing therm om eterswith the ir original form of con striction ; ap art from the
gradation s ,which are som ewhat coarse ,
these app ear on a
laboratory test to b e thoroughly satisfac tory . An auxil iarytherm om eter is provided , an d the glass Jen aer 1 6m and
Vol . are m arked on the stern .
I I .I I IIV .
VI .VI I .VI I I .
LIST OF CHARTS
A I R I SOTHERMS FOR JANUA RY between pages 4—5
IsoB ARs FOR JANUARYSURFACE WATER ISOHAL IN E S 30
—3 1
SURFACE WATER I SOTHERMS 3 4—3 5
OCEAN CURRENTS 60—6 1
D E PTH S 206—207
B OTTOM D E POS I TS 220—22 1
A REA S OF D I STR IB UT ION 2 50—25 1
xviii
2 THE AIR
height of some 300 miles but , so far as meteorologyis concerned
, 20miles m ay be taken as the limit .
The passage of air across a continent is a complexof horizontal and vertical movements , in a medium ofcontinually varying density ; but over the far widerstretches of ocean the density is nearly uniform , varying by but a small fraction of its maximum amount ina horizontal direction
,and falling off uniformly up
wards . The oceans are,in fact
,the only parts of the
Earth ’s surface where it is possible to study theatmosphere in fairly normal conditions . The practicaluniformity of level eliminates differences of pressuredue to gravity the uniform composition of the watersurface eliminates the irregular heating and coolingof the air . These last are due to the different specificheat , conductivity ,
transparency,and power of radia
tion and absorption,which characterize the rocks , sand ,
soil , lake surfaces , and stretches of vegetation , whichdiversify the land
,causing them to react differently
and in various degree to the radiation which is receivedfrom the sun ,
or is emitted from the Earth . Thehomogeneity of the substance and form of the oceansurface favours the normal development of atmosphericequilibrium and adj ustment
,and gives to marine
meteorology a large simplicity,more favourable to the
elucidation of the great laws of atmospheric circulationand disturbance
,than is to be found in the more varied
meteorology of the land . Indeed,it is the effort to
constitute by computation some approach to the S impleconditions of the oceans which leads the meteorologistto reduce to their equivalent values at sea- level , thepressures and temperatures which have been observedon the land
,before the data are considered to be in a
state fit for charting in the ordinary maps of isobarsand isotherms . Being free from —
a multitude of dis
METEOROLOGY 3
turbing causes which are Inseparable from the land , theobserver at sea is among the most favourable conditionsfor investigating normal distributions as well asseasonal and diurnal changes .
There are,however
,special difficulties in meteoro
logical work at sea ,caused by the impossibility of re
maining in one place (for the sea is a highway , whilethe land is a home and the seafarer is always changinghis latitude or his longitude , or both) , and by the restricted accommodation available for instruments ,which make impossible many of the arrangementsconsidered necessary on land . On balancing thefacilities and the difficulties of the study of meteorologyat sea ,
it becomes plain that the advantages resultingfrom the greater simplicity of the problem to beattacked are more than counterbalanced by the greaterdifficulty of attacking it .
Marine meteorology may be said to date from thetime of Admiral Matthew Fontaine Maury , U.S .N
whose Physical Geography of the Sea ,
” though outof date as to facts , and somewhat fantastic as totheories
,remains a model book of popular science
,
written by a man who was possessed of all the knowledge of his time , and afire with the enthusiasm ofresearch . At his instance an International Conferencewas held at Brussels in 1 853 , when a plan was agreedupon for a sort of federated national agency
,each
country undertaking to encourage maritime meteorology , in accordance with general rules drawn up bycommon agreement . As a result , the British Meteorological Office was formed , with world-wide marinemeteorology as its main fi eld of work . The instructions issued by the Meteorological Office and theinstruments supplied through it Should
,
be known toall who undertake any meteorological work at sea
,
THE AIR
although in some points the methods,necessarily
restricted to the convenient use of a mercantile marineofficer without interfering with his more urgent duties ,are capable of considerable expansion in the hands ofa scientific student .
In the United States the Weather Bureau carries onsimilar researches , and the German Naval Observatory
(Deutsche Seewarte) in Hamburg is equally active inthe work . Both the British Meteorological Office andthe United States Weather Bureau issue in advanceMonthly Pilot Charts of the great oceans , on which theaverage meteorological conditions for the month are
laid down .
The introduction by Maury Of sailing directions ,based on a knowledge of prevailing winds and currents ,was of great profit to shipowners by shorteningvoyages
,and stimulated the interest of shipmasters ,
by whom most of our available information of maritimemeteorology was collected in the old sailing- Ships .
The comparative unimportance of weather conditionsin the voyages of modern steamships has led to thepartial neglect of weather observations by sailors ,though the officers of many vessels keep and transmitto the proper authorities excellent meteorological logs .
Brief Sketch of Atmospheric Circulation and
Temperature.
The sun shining on the atmosphere , particularlywhere the ground below is a good absorbent and
radiator of heat , warms it , and causes the air to expand ,
making it lighter , and so reducing its pressure on thesurface . The colder and heavier air of neighbouringregions on which the sun is not shining (either becauseit is night or because of clouds obscuring its rays) is
WIND 5
denser,and thus exercises a greater pressure on the
surface,and tends to spread into the areas oi
' lowerpressure . The air thu s set in motion is wind , and thewind is part of a great and never- ceasing system ofcirculation of the atmosphere of the globe .
Broadly speaking,the heating of air between the
tropics and the cooling of air within the polar circlesare responsible for the whole system of atmosphericcirculation
,including the movement of surface air
from the tropics towards the poles and the returncurrents of air in the upper atmosphere . The factthat these movements are taking place , not on amotionless plane , but on the surface of a rotatingsphere
,accounts for the deviation of the winds from
a north and south direction . I t is convenient toremember that any moving body (whether air , water ,or proj ectile) on the surface of the Earth is caused bythe Earth ’s rotation to deviate towards the right asit moves
,no matter in what direction
,in the northern
hemisphere , and towards the left as it moves , no matterin what direction , in the so
'
uthern hemisphere , theobserver in all cases looking in the direction towardswhich the body is moving . A pole - seeking wind thusacquires a trend from the west as well as from theEquator
,and an Equator- seeking wind acquires a trend
from the east as well as from the pole .
There is an intimate connection between the distribution of atmospheric pressure on the surface and
the direction of prevailing winds,the general relation
ship being that wind blows obliquely from areas ofhigh pressure towards areas of low pressure . The distribution of pressure is expressed in isobaric charts
,
on the same principle as the representation of heightsor depths by contour- lines on orographical maps
,or on
the ordinary sea charts and , in order to deduce from
6°
THE AIR
an isobaric map the direction and force of the wind at
any point , it is sufficient to remember that the windblows from the higher pressure to the lower pressure
,
with a force proportional to the gradient (that is ,to
the closeness with which the isobars are drawn) , and
in a direction tending to the right of a line drawn per
p endicular to the isobars in the northern hemisphere ,and to the left in the southern hemisphere . It mustbe remembered that an isobaric or wind chart for theyear or for a month represents the average conditionfor the year or for that month
,and may not accurately
depict the condition at any particular moment of time .
I f the surface of the Earth were entirely covered bythe sea , so that there was no land to disturb the normalcirculation of the atmosphere , the conditions of weatherwhich actually prevail only in mid- ocean would probably hold good for the whole world
,which would be
girdled by concentric belts of climate as follows1 . An Equatorial belt of permanently low pressureright round the Earth ,
lying approximately along theEquator
,forming a region of calms with ascending
air,in which occasional sharp squalls
,accompanied by
lightning,thunder
,and heavy rain ,
often occur . Thisbelt is the trough of m in irnum pressure , to which thewinds of the whole tropical region blow ,
and on whichall the other pressure belts depend . It would movewith the season
,following the sun northward in the
northern summer,southward in the southern summer
,
and displacing the parallel belts on each side in thesame directions . The belt
,as it actually exists on the
oceans , occupies a m ean position between 5°
and 10°
N . ,
on account of the indirect influence of land ,and as it
swings northward and southward across any givenparallel
,the rainy season of that parallel occurs . The
belt is known to sailors as the Doldrums .
BELTS OF PRESSURE 7
2 . Transitional belts of increasing pressure north and
south of the belt of low pressure,with a steep gradient ,
giving rise to the trade winds,which blow strongly
into the Equatorial trough from the north- east on itsnorthern side , from the south- east on the southern .
This is a region Of high temperature and great evaporation .
3 . Belts of permanently high pressure on the poleward side of the tropics
,respectively north and south
of the trade-wind regions,from which the trade winds
blow . In these calms generally prevail and they arecalled by sailors the Horse Latitudes .
4 . Transitional belts of diminishing pressure, respectively north and south of the belts of high pressure inthe temperate zones
,with south- easterly winds In the
northern hemisphere,and north-westerly winds in the
southern hemisphere,the winds blowing outwards from
the poleward sides of the high-pressure areas .
5 . Two polar belts of low pressure , towards which thewesterly winds ‘
blow,are not so clearly defined , nor
are they so fully investigated as to enable one to speakdefinitely regarding them . The theoretical circulationof air requires them , but it may be that yet anotherarea of high pressure exists at or near the poles themselves .
The surface movements oi air thus described requirefor the completion of the circulation a series of windcurrents in the upper atmosphere practically oppositein direction
,an d observations on clouds and by means
of balloons Show that such currents exist , though ourknowledge of the subj ect is still imperfect .The simple conditions we have outlined do not
actually exist,though over the great oceans there is a
very near approach to them . The influence of land ,
with its diurnal an d seasonal heating and cooling .
8°
THE AIR
extends far over the sea , an d introduces many complications of normal climate due to geographicalposition . The general effect -
of the continents is tobreak up the belts o f high and low pressure round theworld
,the high-pressure belts being most nearly
contin uous in the winter months , the low-pressurebelts most nearly continuous in the summer months ,of the respective hemispheres .
The alternate heat ing an d cooling of continents insummer and winter gives rise to monsoons, or seasonalwinds , blowing from the sea towards the loweredpressure over the heated land in summer
,and from
the high pressure over the chilled continents towardsthe warmer sea in winter . Monsoon winds occur onall continental coasts
,but the monsoons atta in their
greatest development in the Indian Ocean,where Asia
,
A frica ,and Australia combine in modifying the
theoretical wind- directions . Over Asia the monsoonproducing conditions exist in great intensity . . Theresult is that the south- east trade in the northernsummer is drawn northward across the obliteratedbelt of equatorial calms and converted into a southwesterly wind , called the South-west Monsoon
,
which , in many places,blows with the force of a gale .
In the northern winter the north- east trade-wind isgreatly strengthened
,and is called the North- east
Monsoon , but it never attains the force of the southwest monsoon . At the changing of the monsoons ,approximately at the time of the equinoxes
,disturbed
conditions , giving rise to much bad weather , are apt
to occur .
Land and sea breezes, with a diurnal period ofalternation , occur in Similar conditions to monsoons ,but on a smaller scale
, as they are due to the heatingof the land by day an d its cooling by night . The sea
Q
10 THE AIR
m ay be manoeuvred out of the track of the centreafter the approach of the storm has been signalled onboard by the fall of the barometer , the Shift of the wind ,
and the characteristic cloud formation . They are
accompanied by wind of terrific force,falling to a calm
in the centre of lowest pressure the eye of the storm,
where a glimpse of blue sky breaks the pall of cloud) .and rising again as the barometer leaps up ,
to evengreater force than before
,though from a different direc
tion . Such storms in the Indian Ocean and Mozam
bique Channel are called cyclones, and to describethem the word was first devised ; in the West Indiesthey are called hurricanes, an d in the China Sea
typhoons. The rapid fall of the barometer to an
extremely low point,an d its equally rapid rise
,is the
most s triking characteristic of such storms from themeteorological point of View . A synoptic isobaricchart
, Showing the pressure at the same moment at alarge number of points during such a storm
,exhibits
a series of concentric,nearly circular isobars
,the
lowest in the centre ; and successive charts at shortintervals of time show that the storm travels withmore or less regularity in a curved path
,which ,
as a
rule , can be fairly accurately forecasted by observationso f the wind and the movements of the barometer .
These storms move from the tropics first in a polarwest direction
, and later in a polar east directionin other words
,their track is at first towards the
west,curving as they proceed towards the right in
the northern hemisphere, and towards the left in the
southern hemisphere .
We know little or nothing at present of the generationof these violent cyclonic storms
,though from the fact
that the appearance and movements of cirrus , thehighest form of cloud , usually give the first signal of
AIR TEMPERATURE 1 1
their approach , even before the barometer begins tofall , i t seems not improbable that the study of the condition s of the upper atmosphere m ay throw some lightupon the problem . Storms in general appear to beeddies in the steady flow of the great air currentswhich carry on the normal circulation of the atmosphere
,and they are apparently fed from the per
manent high-pressure areas .
The storms of high latitudes (such as the extratropical parts of the North Atlantic
,the North Pacific
,
and the Southern Ocean) are most frequently cyclonesof far less intensity than those of the tropics
,but in
volving a very much larger area of the ocean surfaceand travelling with much greater velocity ; but onaccount of the gentler pressure -gradients the winds arerarely of such intensity
,though frequently of longer
duration . There are some peculiarities,still im
perfectly understood,in the storms of the Southern
Ocean,which require elucidation . Speaking generally ,
the force of the wind depends only on the pressuregradient a gr eat fall of the barometer in a longdistance may produce a much l ighter wind than asmall fall of the barometer in a very short distance .
The use of wireless telegraphy now permits ships atsea to compare their barometers and so to measurethe gradient directly but where this is not possiblegradient can be j udged by the rate of fall of thebarometer . Thus
,a fall of a tenth of an inch in half an
hour shows a far steeper gradient , and forecasts farstronger wind
,than the fall of a whole inch in ten or
twelve hours .
Observations Show that the air temperature over theopen ocean is subject to a much smaller diurnal andannual range than over the land . I t is only in suchenclosed waters as the Red Sea and the Persian Gulf
i2 THE AIR
that very high temperatures are the rule , even withinthe tropics ; while low temperatures prevail only inthe vicinity of the Arctic and of the Antarctic regions .
The borders of an ocean,in which the prevailing wind
is off- shore , in the tropics frequently Show a loweredair temperature , on account of the cold upwellingwater drawn up from the depths by the blowing awayof the warm surface water . On the other hand , theborders of an ocean in which the prevailing wind is onshore
,often has a higher air temperature on account of
the warm surface water driven in from lower latitudes .
What may be termed normal conditions of tem
perature are considerably deranged by local causesin different parts of the globe—as , for instance , off
Cape Guardafui , on the East Coast of Africa , wherethe changing of the monsoons substitutes an on - Shorefor an off~ shore wind ,
giving rise to upwelling of coldwater and banking up of warm water alternately .
Other instances are found off the Cape of Good Hope ,the Banks of Newfoundland and the Falkland Islands ,where ocean currents of different temperature meet ,and the same area is occupied at different times bywater of varying origin and temperature , which reactson the air .
Instruments.
I t m ay be remarked that , as’
a rule,there is not
much choice in the placing of meteorological in struments on board ship ; this follows from the structureof the vessel and the exigencies of her special service .
Besides , the instruments must be placed in the handiestposition for observers
,who may have to consult them
without quitting their posts or otherwise interruptingthe duty of the moment hence the routine Observation smade on board Ship
,useful as they are ,
l eave a good
BAROMETERS 1 3
deal to be supplemented when opportunities are offeredto scientific observers .The most important of all meteorological in stru
ments at sea is the barometer , for all our knowledgeof the cause and general prevalence of wind and thebroad lines of atmospheric circulation depends uponexact and multitudinous measurements of pressure .
1 . The mercurial barometer must be hung in avertical position
,and should be placed in a room with
a temperature as equable as possible , free fromdraughts
,in a good l ight , and at a convenient height ,
so that the eye can be brought easily to the l evel ofthe top of the mercury column . These conditions arej ust as imperative at sea as on land , though much moredifficult to fulfil . At sea a vertical position can onlybe preserved by a barometer so freely suspended thatthe ship can roll without affecting it . Even with thebest arrangement of gimbals this is practically impossible
,except ih a very smooth sea ,
and the mercuryin the ordinary barometer surges up and down so asto make accurate measurement extremely diffi cult .The surging of the mercury due to the ship
’
s motionis checked in marine barometers by a constriction ofthe tube at the cistern end
,so that the action is
slowed down . A more serious cause of disturbancearises from the action of the wind during heavyweather . The barometer is most conveniently hungin the chart- room of a modern steamer
,from 20 to
60 feet above the sea- level . In this room the windward door is kept shut and the leeward door open ;and as each gust of wind sweeps past
,the air is sucked
out through the open door,and the mercury in the
barometer sinkS '
to the diminished pressure , rising againin the lull and continuing to swing up -and downwhile the pumping action lasts . Great skill and
‘
1 4 THE AIR
dexterity are required in setting the vernier so as toallow for this pumping , and even in the best in struments
,with the most alert and patient observer
,it
is impossible to read with anything like the degreeof accuracy which may be obtained at stations onland . The rise and fall of the Ship with the wavesproduces a smaller irregularity ,
and when it is re
membered that , roughly speaking ,the barometer falls
one- thousandth of an inch for every foot of increase ofheight
,it is plain that the vertical rise and fall of a ship
in rough weather may affect the readings by severalhundredths of an inch . It is necessary
,therefore
,in
any attempt at exact work , to take the mean of thehighest and lowest readings when the ship is in thetrough and on the crest of successive waves . It mustbe remembered that a greater degree of accuracy inreading the barometer is required for meteorologicalpurposes than when the barometer is merely used as a
nautical instrument to give warning of storms . Thebarometer must be kept as free as possible from artificial heat and from risk of jars or knocks but when itis suspended in suitable gimbals it does not requireany extra springs or strapping .
2 . The aneroid is a useful supplementary in stru
ment ; as it is more sensitive than the mercurialbarometer
,it gives earlier warning of approaching
weather . It is free from the surging error due to therolling and pitching of the ship ; but no barometercapable of measuring differences of pressure canescape from the disturbances due to the pumping produced by suction of wind and to the rise and fall ofthe waves . A barograph, or self- registering form ofaneroid ,
is,perhaps
,the most suitable on board Ship .
If hun g with a spring hook to the roof of a cabin , i tgives a continuous record
,of the utmost value when
THERMOMETERS 1 5
checked by periodical readings of the mercurialbarometer . Specially sensitive patterns
,provided with
a drum revolving more rapidly than in the ordinaryform
, may be used to keep a record of the height of thewaves encountered .
3 . Temperature is measured by thermometers, whichshould be of standard type , tested at Kew or at someother national testing establishment , and supplied Witha certificate of accuracy . This condition is insistedon for all the instruments supplied by the Meteorological Office for use at sea . The wet and dry bulbthermometers must be exposed in a louvred screen
,
quite in the open , free from all artificial heat , and protected from sea- spray and from all risk of inj ury . Thebulb of the dry thermometer must be kept as free frommoisture as possible , and the bulb of the wet therm om eter free from salt . The obj ect of the wet bulbthermometer in conj unction with the dry bulb is tosupply data for calculating the humidity of the air
,for
which purpose tables are printed in all books ofinstructions for the use of meteorological instruments .
The wet and dry bulb thermometers,used for
measuring the temperature and humidity of the air ,act as well at sea as on shore but the water suppliedto the wet bulb and the muslin covering the bulb mustbe more frequently changed , to prevent incrustationwith salt . A weekly change of muslin and the use ofdistilled water would probably be found necessary , inorder to obtain accurate results . A more seriousdifficulty which arises is the totally inadequate character of the Board of Trade screen usually suppliedfor housing the thermometers . This is too small , andits place Should be taken by an ordinary Stevensonscreen
,as employed On shore . The great Size of modern
steamers gives ample room for setting up such a screen ,
16 THE AIR
which Should be placed forward of the funnels and
galley chimneys and on the highest accessible part ofthe Ship
,so as to keep it freely exposed to the wind
,
but clear of spray except in the worst weather . Themiddle of the forward end of the roof of the chart- roomis the ideal position . Better resultS
'
would probablybe obtained by the use of Assmann ’s aspiration
psychrometer. This consists of a wet and dry bulbthermometer placed side by side in metal tubes
,over
which air is drawn by a quick—running fan, actuated
by clockwork . I t can be used in full sunshine,and
the observer Should stand on the windward side of theupper deck , the instrument being kept in a case safelystowed away between the times of reading .
Maximum and minimum thermometers of theordinary type could not be used on board ship hitherto
,
on account of the liability of the indices to be displacedby the rolling but on the largest vessels of the presentday there seems no reason why they should not beemployed with perfect safety on most days
,if they are
placed fore an d aft in the thermometer screen . Butin any vessel a maximum and minimum thermometerof Six’s type can be used alongside of the wet and drybulb thermometers
,and the results of such observations
would be the more useful because,as yet
,they are very
rare . The best form would be one of the large-patterndeep- sea thermometers , which for this purpose neednot be provided with an outer protective bulb . A
thermograph hung by a spring hook from the roof of awell- exposed Stevenson screen would yield mostinteresting results , but everything depends on theexposure being free to the wind and protected fromthe rain
,and spray , while the clock would require
to be carefully attended to and set daily to ship’
s time .
It would . probably be of little use to attempt to
THE AIR
Other Meteorological Phenomena.
Clouds may be observed to perfection at sea ,where
nothing interferes with the wide prospect from horizonto horizon . There are three main types of clouds :cirriform,
or wisp clouds cumuliform,or heap clouds
stratiform, or layer clouds . D ifferent classifiers ofclouds have subdivided these main types into severalvarieties
,and it would be a useful exercise to compare
the different classes , which have for the most part beenmade from observations at a shore—station in temperatelatitudes
,with the forms seen at sea in all parts of the
world .
For many purposes the broad division into threetypes suflices . It is noteworthy that one type of Cloudprevails more than the other in certain ocean localities .
In the north- east trade region great masses of stratusabound , while in the south- east trade district thecumuliform predominates . In the doldrums an d thehorse latitudes the cumulus type prevails
,often in the
most curious and remarkable forms . In the northeast trades cirriform clouds are constantly to be seenmoving away to the north- east from a south-westerlydirection .
Fogs are of such serious importance in navigationthat they are naturally obj ects o f much interest at
sea . Certain regions are almost constantly beset byfog—off the Newfoundland Banks , for instance , wherethe icebergs brought down by the cold water from thenorth meet the warm water coming from the south .
Fogs are common ,also
,in the corresponding districts of
the North Pacific and off the Falkland Islands , wheresimilar causes operate . Dense fogs frequently occurround the coasts of England in the early winter months ,
RAINFALL 1 9
when the sea surface is much warmer than the air butsea fogs cannot always be accounted for in this way .
Rainfall .—There is no department of marine meteorology which has been so n eglected
'
as the measurementof rainfall
,and we have only a few fragmentary obser
vation s to go upon in comparing the rainfall of the landwith that of the sea . In this instance , again ,
the largesteamers of to -day offer facilities for accurate obser
vation s which were formerly unknown ,though fair
results have been obtained even on a vessel so small
as the D iscovery , of Captain Scott’
s first Antarcticexpedition . The rain-gauge for use at sea must beswung on gimbals
,and the lower part heavily loaded
so as to keep it as horizontal as a compass bowl .It should be placed in the middle of the upper deck
,
as far as possible from masts , funnels , or stays , andfrom the Sides of the ship . The two chief difficultiesto be overcome in measuring rainfall at sea are ascending eddies of air and the breaking of spray into thegauge . The eddies m ay be neutralized to some extentby preventing the wind from striking directly on thegauge or the box in which it swings this may be doneby having a wooden frame fixed to the deck
,with walls
equal to the height of the gauge , and of such a size asto be at least as far from the gauge as its own heightat every point . The amount of sea water which findsits way into the gauge can easily be calculated bydetermining the salinity of the contents of the gaugeby titration
,for which all appliances would be found
on any . vessel fitted out for marine investigations . I fit were found practicable to instal a rain -gauge on anordinary steamer
,i t would probably be as much as
could be done to record,every time the gauge was
emptied,whether the contents tasted quite fresh
,or
were Slightly or very salt . I n the first case no cor
20 THE AIR
rection is required in the last case,unless it is known
that rain fell , the contents could be treated as all dueto spray ,
and thrown away unrecorded ; but if thewater is Slightly salt , a note must be made of the fact ,an d the measurement entered with a query . Muchvaluable information could be obtained
,even without
a rain—gauge,if the time when rain began and ceased
were recorded in the log , . with a descriptive note as
to whether the fall was light , heavy ,or torrential .
It is surprising that so few ships’
officers have thoughto f recording this almost unknown factor of sea climate .
The Upper Atmosphere.
Until quite recently we had no practical means oftaking observations in the upper regions of theatmosphere , but of late many experiments have beenmade
,by means of kites and balloons
,which give
excellent results ; and the upper atmospheric regionsare being gradually explored and systematicallystudied . Recent research on the temperature and
other conditions in the free air at great heights haveshown that normally the temperature falls rapidly asthe height increases , until an elevation of six miles
(more or less) is reached,
. where the temperature isfrom 30
° to 70° below zero Fahrenheit
,after which there
is practically no further decrease of t emperature , butsometimes a distinct increase . The upper region ofnearly uniform temperature has been term ed byphysicists the isothermal layer
,or
,less aptly still ,
the isothermal column . It might be better named
( in con formity with the nomenclature recognized byoceanographers for the depths) the homothermicregion . NO vessel specially equipped for oceanographical research should be without. a supply of
UPPER ATMOSPHERE 2 1
meteorological kites , with the necessary wire and winchand Special meteorographs ; for ascents can easily bemade from a Ship , which can be manoeuvred to helpthe Wind in raising the kite but no direct investigationof the upper air is practicable on a vessel which cannotdeviate from her course . A good deal can be done ,however
,to determine the direction of the upper
air currents by letting off small balloons (pilot balloons ) ,an d measuring the angle of altitude of the liberatedballoon by means of a sextant at uniform intervals oftime
,and the azimuth at the same intervals by means
of a compass provided with suitable sights . Thealtitude angles give the distance of the balloon fromthe ship on the assumption that the rate of ascent isuniform , the time intervals thus giving the heightabove the sea at each observation . The rate ofascent for balloons of a given Size
,material , and
amount of hydrogen,must be determined by measure
ments on land,by two theodolites at the ends of a
measured base . The azimuths,taken in conjunction
with the ship ’s course and speed ,Show the direction
of dr ift of the balloon as it rises—that is , the movementof the wind at the given heights .
Without the use of any instruments the characterand movements of the upper clouds are an indicationof the winds in the higher regions of the atmosphere ;and, when travelling in places where volcanic eruptionsmay occur , the observer ought to take particular noteof the form
,angular height
,and direction of drift of
any column of steam or smoke which m ay be seen to bethrown up by a volcano . It may be recalled that thedust of the eruption of Krakatoa
,in 1 883 , which was
proj ected to an observed height Of twenty miles ,was carried by the upper currents of air ,
not only all
round , but all over the world . In all. observations
22 THE AIR
involving direction the utmost care must be taken tostate clearly whether each reading is magnetic or true
,
and, if magnetic,the true bearing should be calculated
and entered as soon as the variation is known . Muchtrouble has arisen through the neglect of this veryobvious precaution .
Special Problems in Meteorology.
Meteorological observations at sea on a scientificexpedition are of great importance with reference tooceanographical observations
,such as the temperature
of the surface water and of the deeper layers , thesurface currents
,the occurrence of plankton , and other
matters . But it is also important to consider meteorological observations from the point of View of ourknowledge of the science of meteorology itself , and
there are some problems which are more likely to beelucidated by observations at sea than by those onland . One of these is the angle with the horizontalmade by the wind when it strikes the sea and the effectof winds of different degrees of obliquity . So far as
we know, nothing has been done in this direction butit is obviously of importance
,with regard both to
wind- raised waves and wind- driven currents . How
such observations can be made we must leave to theingenuity of the investigator
,whose attention has been
called to the subj ect .
Another matter,concerning which more information
is required, is the diurnal variation of phenomena . The
hours at which the two maxima and minima of pressureand the maximum an d minimum temperature occur ineach diurnal period can be determined only roughlyfrom routine observations
,and it is worth while to
supplement the regular readings with more frequent
SPECIAL PROBLEMS 23
readings about the critical hours,or
,still better
,with
the tracings of self- recording instruments .There are innumerable opportunities at sea. for the
observation of other meteorological phenomena and
weather conditions for which no special in strumentsare at present available
,or
,indeed
,required . Such
phenomena , as being of only occasional occurrence ,should always be recorded
,not because of their rarity
or their impressiveness,but because
,as the times of
their appearing cannot be predicted,and few are found
ready when the phenomenon is suddenly recognized ,
there are very few cases on record of exact measurements . Among these are squalls , waterspouts , thunderstorms , wind-borne dust
,and Optical and electrical
phenomena .
Waterspouts Should , if possible , be photographed ,
the course of their formation and dispersion carefullywatched and desc’ ribed
,and an endeavour made to
obtain angular measurements which will give thedistance and height of the columns and their rate ofmovement .
The optical phenomena include rainbows,rin gs round
the sun an d moon (known as coronae , halos ,paraselenae
,sun pillars
,and the green ray .
These phenomena give the most striking effects at sea ,
where —they are seen much better than on land . Thesun shining on the drops of a passing shower producesthe rainbow by double internal reflection sometimesa double or outer bow is . visible . Rainbows are oftento be seen at night
,when the moon is particularly
bright . Coronas are due to rays of the sun or moonshining through loose clouds of either the cumulus orthe stratus variety : they give the effect of faintlyoutlined rings round the orb . Halos and the otherforms of ring are due to sunlight shining through
‘
24 THE AIR
very high cirriform clouds,in which ice crystals re
place globules of water . These halos present verystriking and beautiful effects , but the more complicatedformations of rings are rare . Careful observationsShould be taken of all such phenomena , not only because they are often the first indication of an approaching storm
,but because of their intrinsic interest . Thus ,
for example,a halo when observed should have the
angular diameter of the main ring measured by a sex
tant,and the diameters of any fragmentary circles esti
mated by measuring the visible arcs . The height of thesun or moon above the horizon
,the hour
,and the state
of the sky as regards clouds,should all be noted . A
sun pillar is also a rare phenomenon this is a pillar oflight which ,
as the sun sets,shoots directly up into
the sky for a space of from 10 to 1 5 degrees , remainingstationary for some little time . The light appears tobe reflected from the under- surface of ice crystals , as. alight may be reflected from a water surface . A veryrare and beautiful phenomenon m ay sometimes beseen at sunrise or at sunset pink rays springing up onthe horizon , opposite the sun ,
and sometimes reaching to the zenith . The phenomenon
,known as
the green ray at sunset and sunrise,is the brilliant
green colour which the line bounding the upper limbof the su n assumes when it is j ust touching the waterhorizon . It is curious that
,although plainly visible
to the naked eye,the old navigators do not appear to
have noticed it . The theory of this appearance isfully understood
,but it may be used as a test of the
observers ’ vision .
Amongst the electrical phenomena we have—apartfrom lightning—the aurorae and St . Elmo
’s fires .
The sometimes radiant appearance of an aurora m ay
indicate a connection between this phenomenon and
C HAPTER I I
THE WATER
BY H . N . D ICKSON AND D . J . MATTHEWS .*
OUR knowledge of the physical geography of the sea,
of its depths , the composition and physical conditionsof its waters , and their movements , is wholly derivedfrom observations made from the surface . Surfaceconditions themselves can of course be observeddirectly from on board Ship . Observations in thedepth must be made indirectly—Le ,
by means ofinstruments , which can be sent to the point at whichit i s desired to make an observation and caused torecord a
-
Condition there , or to bring back a samplefrom which the condition m ay be inferred .The work of the earlier deep - sea expeditions , suchas those of the Challenger , brought two fundamental facts to light . I t became clear first that theconditions in some regions of the sea vary withincertain fairly narrow limits . Some of these variationsare periodic
,some non- periodic
,but a knowledge of
their range from season to season and from year toyear is of the highest scientific and economic importance . Such knowledge is gained by repeatedobservations from large numbers of vessels , distributedover a wide area,
and observing as far as possible
Of the jo in t writers of this chap ter ,D r . D ickson has c on
tributed the m ore theoretical p art , Mr . Matthews the p racticalsection —ED .
NEED FOR OBSERVATIONS 27
simultaneously . Work of this kind attains its highestdevelopment in such special organizations as those ofthe International Committee for the Study of theSea, or the combined Antarctic expeditions ; but muchuseful work can be done by Ships cruising in areasoutside the field covered by these organizations
,as
in the expeditions of Dr . Wolfenden’
s Walwin and
Silver Belle , or in almost any region ,by ships taking
regular routine observations of a more or less elaboratecharacter, and communicating the results to a centralauthority , such as the Meteorological Office , forcollation with the records of other observers . As
examples of what may be done in this way fromsurface observation alone , reference may be made tothe surface temperature charts published officially inthis country , the United States , and elsewhere , andthe surface salinity m ap which illustrates this chapter .
All these depend on the daily observations made onboard liners , tramps , whalers , yachts , and oceanfaring craft of all descriptions .
The second fundamental fact is , that in all oceansthe conditions below a certain depth are very uniformover a considerable horizontal and vertical range , andchanges take place with great slowness if they occurat all. Now
,observations in the depth must be made
from vessels of considerable size,
“
and with somewhatelaborate and expensive equipment but the minimumtonnage is well below that common amongst oceangoing steam-yachts
,and the cost of the necessary
equipment is not of an order of magnitude greaterthan other outfits in such vessels . And the conditionsj ust explained make observations of this kind valuable,wherever and whenever they are made ; for the greatlines of soundings laid down by the deep - sea ex
peditions and the cable ships are separated by vast
28 THE.
WATERareas in which charts
.
Of all sorts remain blank to thisday , even as regards the depth ; and we know thateach point filled in by a new sounding is , beyond acertain depth at least , practically filled in once for all.Thus there are , so far at least as physical oceanography
is concerned , two distinct kinds of work waiting to bedone—the work at the surface and in moderate depths ,which can be undertaken more or less fully by practically every Ship that puts to Sea and the work in theabysmal depths of the unfrequented parts of the greatoceans , which can be done by larger vessels , morefully equipped and not restricted as to route or time .
The following may be taken as the principal observations common to both types of work . It beingassumed that a vessel has arrived at a definite pointin the
.ocean , the latitude and longitude of which are
known , information is wanted on the following points
1 . Depth .
2 . Temperature of water at surface,bottom , and
intermediate depths .
Composition of water .Specific gravity of water .
Currents .
Nature of bottom .
The first and last of the above headings are dealtwith in another chapter , and we need only note here .
with regard to the first,that the collection of material
under the headings (2 ) and (3 ) can only be associatedwith those methods of sounding in which the measurement by vertical sounding- line is concerned themethods depending on measurement of pressure , as inKelvin ’s sounder
, are inadmissible .
The obj ect of‘
making these observations , and ofcollecting samples of water , being ultimately to asoer
G
UI
-R
U.
)
COMPOSITION OF SEA WATER 29
tain the geographical d istribution o f the variouselements , and the changes which take place in them ,
some general considerations may be stated beforeproceeding to detailed description of the methodsemployed .
Composition of Sea Water .From comparison of all available analyses of sea
water, it may be assumed that the composition of seawater in the open oceans is the same in all parts ofthe world—that is to say , ocean water containscertain salts in solution
,and the relative proportions of
these are constant (see Addenda ,p . xvii) .
Their most important features are—(a) the preponderance of sodium chloride ; (b) the small proportion of calcium carbonate ; and (c) the residuumof 0-22 per cent . , which contains traces of nearly allthe known elements
,including gold .
There is thus present in all oceans a brine ofparticularly constant composition
,and the variations
which are observed in the composition of sea waterconsist merely of variations in the extent to whichthis brine is diluted
,j ust as variations in tea made
from the same leaves consist in variations of strength .
Hence one of the most important factors to be determ ined in physical oceanography is the strengthor sal inity of the water at different points and atdifferent depths . The salinity of a sample of waterserves as a label
,which often makes it possible to trace
its origin and physical history and hence to draw conclusion s repecting currents , and ,
along with its tem
perature in place , enables us to calculate its specificgravity .
“
The salinity is the total weight of saltsin bulk in solution In a given weight of water ; thus ,Salinity 3 5 per mille means 3 5 pounds of salts in
30 THE WATERpounds of the water solution . Specific gravity
is the weight of a unit Volume of the water solutionit varies with temperature as well as with salinity ,
since water expands when heated and contracts whencooled .
That the determinations of salinity must be madeaccurately appears from the fact that the total rangeo f variation in the open sea is at most between 3 3 and
3 7 per the average salinity running between
3 5 and 36.
The chart which follows Shows the general distribution of salinity in the oceans so far as it is known ,
but it must be understood that in many regions,where
actual observations are few and far between,the
isohalin es (lines of equal sal tness) are drawn witha free hand (compare Chart IV . with this) .A study of these charts shows at once the general
nature of some of the problems which a knowledge ofsalinity helps to elucidate
,and which depend for their
complete solution , in part at least , On a more intimateacquaintance with the local distribution in certainseas , and the changes which occur .I t appears (a) , that the saltest surface water is
found in the trade wind belts,where strong sunshine
and steady winds favour great evaporation . Frommaps of Specific gravity it appears that the hightemperature of the water keeps it relatively light ,notwithstanding its great saltness , and hence we haveto inquire as to the sources whence the deficiency ofwater due to removal by evaporation is made good .
Again (b) , the freshest surface water occurs in eitherregions of widespread excessive rainfall such as
the Western Pacific—or regions in high latitudes ,where cold fresh water is set free by the melting offloe- ice and icebergs . The investigations of the last
TEMPERATURE OF SEA WATER 3 1
few years have shown that the distribution of this coldwater
,which varies greatly from season to season ,
and from one year to another , has a profound effectupon climate and upon the distribution of marinelife (including food-fishes) , and m ore
'
observations inthis direction are urgently needed .
This fresh water is relatively light , notwithstandingits low temperature
,but
,when it moves into lower
latitudes,its specific gravity tends to increase frela
tively to the warmer water surrounding it hence wehave a zone of maximum specific gravity at thesurface outside the latitude of the trade winds , a sortof combined effort of warm salt water on one Side andcold fresh water on the other .
Lastly (c) , the complete mixture of waters in theoceans frequently takes place with great slowness
,
compared to the rate of the horizontal movementsknown as currents hence , fresh or salter water mayoften be traced for great distances merely by thedifference in salinity from adj acent parts of the ocean .
The opportunity which a knowledge of salinityaffords in this way of tracing the course and volumeof currents gives these observations their greatestvalue .
Temperature of Sea Water .The distribution of temperature at the surface and
in the depths is shown in Chart IV .
By this distribution several distinct questions areraised
,all of which require more material for full
discussion ; but we may call attention to two mainpoints1 . Assuming the waters of the sea to be at rest ,
what are the main Sources of gain and loss of heatwhich determine their temperature ? The surface of
3 2 THE WATERthe sea differs from that o f the land in that it is notopaque , but to a certain extent transparent at leastto certain rays of light . Buchan Challenger Report )found evidence that the effect of the sun ’ s rays wasappreciable to a depth of about 500 feet from thesurface in deep water ; more recent experiments havetraced it to still farther depths . Radiation must go onto a certain depth , resulting in larger or smaller variations of temperature . Again , the surface of the sea is incontact with the air the latter is constantly changingits temperature , and these changes must be commun icated -to the sea water by conduction . Thecombined results of these factors are given by Buchanwho found that on the average of all the Challengerobservations a diurnal range of the temperature in theair is three to four times that of the surface waters ofthe sea over which it lies .
2 . The variations of temperature , taken along withthose of salinity, determine variations in specific gravityin the manner already described , and they also furnishvaluable additional means of tracing the maj or movements in the depth .
With regard to the actual methods of investigation ,
it m ay be definitely laid down that observations ofthe temperature and the currents must be made at
sea ; but determinations of the density and chemicalcomposition
,with suffi cient accuracy for modern re
quirem en ts , can only be carried out on Shore . Analysisof the dissolved
“
gases is a possible exception to thisrule
, and reference should be made to the variouspapers which have been published on the subj ect .Samples of water must therefore be collected for
34 THE WATERSuitable boxes for packing the 6—0unce milk bottles
can be obtalned from the glass makers . They Shouldbe divided into compartments , so that each bottle isseparated from the others , and both bottom and lidShould be lined with felt . No further packing is
required . The boxes should have‘
a hasp and staplefor closing , and rope handles should be fitted . Handholes give admission to rats
,which eat the labels .
Care should be taken to rinse out the bottlethoroughly with part of the water
, and not to fill thebottle within (say) an inch of the stopper . Frostshould also be guarded against one of the writers haslost a number of samples from this cause .
T he particulars (i.e name of ship ,date , time ,
latitude and-longitude , depth ,
and(temperature) shouldbe written on stout Manilla paper labels , and tied tothe bottle , the string being fastened in such a way asto obviate any possibility of the catch springing up .
The number of bottles in each box will vary accordingto circumstances . Suitable numbers are thirty , thirtysix, and forty- two . For larger quantities of water ,imperial pints of the same shape m ay be used .
Surface water is easily collected in the bottle itselfor in a bucket ; as the bucket will also be used fordetermining the temperature it is somewhat difficultto decide on the best material . I t must be easilywashed free from dried salt , and from this point o fview a non-porous material , such as metal , is mostsuitable . On the other hand , a metal bucket allowsthe temperature to change so rapidly , that it is at
times impossible to obtain a correct reading . Woodgives accurate temperatures , but requires very carefulwashing to free it from salt . The author prefers touse a rivet ed leather bucket for surface samplestaken under way ; but if the vessel is stopped and
THERMOMETERS 3 5
investigations are being.m ade at various depths,it is
better to use the deep - sea water-bottle for the surfacealso
,if the weather permits of this being done .
Below the surface , water samples must be collectedby means of some apparatus which can be closed atthe required depth . There are many forms which are
suitable , and as they are generally made to carry a
thermometer the latter may be discussed here .
There is one rule which is of the greatest importance—that is , that no thermometer is to be used unlessits errors are known . All the forms of thermometerused for marine investigation can be bought with acertificate of examination at some recognized in
stitution . In England the examination is made atKew
,in Germany at the Physikalisch-Technische
Reichsanstal t at Charlottenburg . I t Should be re
membered that the error is stated in different ways .
The Kew certificate gives the correction to be appliedto a given reading in order to find the true temperature .
Thus,if the thermometer showed 10
° and the correc
tion is given as —0 the true reading would be thesum of the observed reading and the correction—thatis
,The German certificates give the error —0-1 °
here would mean that the thermometer read 0-1°
too low,so that the true reading would be 10 The
certificate can , of course , only Show the errors at thetime of examination , and these errors may be callederrors of graduation .
There is , however , another error which is to beguarded against . The glass of the thermometer continues to contract Slightly for years after it is made
,
and so causes a Slow rise in the zero . In order todetect this the thermometer Should be tested at intervals , either by comparison with a standard in strument of known accuracy, or better by means of
36 THE WATER
melting ice . The thermometer is immersed in pureice that has been crushed and washed with distilledwater
,so that the graduation , 0
°C . or 3 2
° F is justvisible . The vessel containing the ice should havean opening to permit the water formed to run away,and sufficient time should be allowed for the temperature to become steady . The best way is to makereadings at intervals , tapping the thermometer lightlybefore each , until no further change is noticed . Thecomparison must be carried out in a room with a
temperature above freezing- point , otherwise no meltingwill take place , and the greatest care must be takento see that the ice is pure ; any dissolved salts willlower the freezing- point .
The error of the zero -point , i f any ,will be applied
equally to all temperatures in addition to the errorsshown on the certificate .
The rise of the zero -point m ay be avoided to a certainextent by using old thermometers , and some makersgraduate their instruments only many years aftermanufacture or the special thermometer glasses m ay
be used,such as the Jena glasses 59 I I I or 1 6 I I I . In
any case , however , the instruments should be verifiedat intervals .
I t may be taken as a general rule that it is notpossible to estimate the subdivision Of a small intervalby eye more closely than to one- tenth , though someobservers can pass this limit of accuracy with thegreatest ease ; it follows , there fore , that no correctionneed be considered , for hydrographical purposes ,which is less than one- tenth of the smallest divisionshown .
If the surface temp erature alone is to be observed ,
an ordinary chemical thermometer , divided to C . ,
is as a rule sufficient . though one more finely divided
INSULATING WATER-BOTTLE 37
m ay be used . It i s not often , however , that a surfacereading can be trusted to less than 3
1
3
°
and theuncertainty is generally far greater . The most usefulkind is that known as a milk-glass scale therm om eter ; the graduations are marked on a strip ofwhite glass , which is protected from the water by . anouter glass tube . These thermometers have no metalframe round them , and as they can easily be cleansedfrom salt it is allowable to use the same bucket ofwater for reading the temperature and bottling a
sample . A very useful pattern is that used by theBritish Meteorological Office the glass is protectedby a metal frame , and is not easily broken ,
but as thebulb is surrounded by a small bucket , which may holddried salt , a fresh lot of water Should be used for thecollec tion of a sample .
A very large number of water-bottles have beendevised for the collection of samples of water belowthe surface , and the description will therefore beconfined to that with which the authors are practicallyacquainted . For moderate depths , by far the bestinstrument is the Nansen-Pettersson insulated waterbottle , which has been made in various sizes , and canbe closed either by a messenger
,
” or by a propeller .
The Insulating
l
Water-Bottle.
The Nansen-Pettersson insulating water-bottle , in itslatest form , is an instrument by means of which it ispossible to lower an ordinary thermometer , enclosedin an outer tube to protect it against pressure , to thedesired depth
,and there to surround it by a number of
envelopes of the water to be examined . I t can thenbe hauled up through layers of widely different temperature without the thermometer showing any ap
F IG . 6 .—NANSEN -PETTERSSON
WATER-B OTTLE (O PEN) .
Cover o r upp er p late .
Hooked lever ho ld ingbottle op en .
Striker p late .
Sp rings ho ld ing up striker p late .
Therm om eter guard .
Catches ho ld in g therm om eter
guard in po sition ; on e alsoacts as air valve .
g,A ir tube .
h, Outer cylinder .
B ottom p late .
Adjustable lugs .
k, (dotted lin es ) , Lo cking leverwhich engages with the lugwhen the bo ttle is c losed .
S inker .
m ,Large rubber washer .
n ,Ou tlet for water .
Sm all rubber washers .
Inn er in su lating cylinders .
Nut ho ld ing therm om eter .
Nan sen Therm om eter .
Extra fram e fo r reversing ther
m om eter .
Swinging arm s .
D istan c e p ieces .
O
Q
&
Q
S
N
R
a
m‘fi
INSULAT ING WATER-BOTTLE 3 9
preciable change within a period of from six to eightminutes , which is amply suffi cient for the moderatedepths for which it is suitable . At greater depths thereadings become inaccurate on account of the pressure ,as will be explained belowThe construction will be understood by reference
to the figure . The b ody of the water-bottle consistsof a number of concentric cylinders , of metal an d somenon- conducting material alternately
,and is fitted to
slide freely on the two guide bars at the Side . Thesebars are connected at the bottom by a metal platefitted with a tap and a number of rubber washers .
A similar plate is arranged to slide on the guide barsabove the body of the water-bottle
,and instead of a
tap it is provided with a small air valve and a centralhole , through which the bulb and the lower part of thestem of the thermometer pass they are secured by agland and rubber washer . A thermometer guard , inthe Shape of a slotted tube
,is fixed to the upper side
of this lid and carries two hooked arms at its upperend . To set the water- bottle for use ,
the lid is raisedand the hooks at the top of the thermometer guardare made to engage with the lower part of the spindleof the releasing gear . The striker plate is then raisedand the lid is fixed . The body of the water-bottle isnext raised until the lugs
,which proj ect on each side
from its upper rim,engage with the two swinging arms
shown pivoted to the lid,and the two small locking
levers at the end of the arms are folded upwards , untilthey pass a spring catch which holds them in position .
The lid , body ,and bottom plate are now held apart
from one another so that the water can pass throughfreely . The taps and air valves are then closed , andthe water-bottle is lowered to the desired depth bymeans of a steel cord passing through the striker plate .
40 THE WATERAfter allowing it to remain down for two or threeminutes to take up the temperature of the water , aweight or messenger is fixed over the Wire andallowed to Slide down until it hits the striker plate .
This releases the catches at the top of the thermometerguard ,
and the lid falls on to the body and the twotogether fall on to the bottom plate . The two lockinglevers open and engage with the locking lugs on theguide bars and keep the water-bottle tightly closed .
The lugs are adjustable , and their position can bealtered if necessary . Before the bottle can close it isnecessary that some water Should escape through a
relief valve fitted under one of the catches of the therm om eter guard , and the time required for this can bedetermined by making an experiment just below thesurface or in moderately good weather one can feel theshock of the water-bottle closing , by keeping one
’s handon the wire . After allowing a sufficient interval forthis purpose , the bottle is hauled up as quickly as
possible,and the temperature is first read . At night
an electric torch,held behind the thermometer , 18 of
great assistance . One of the air valves in the lid isthen opened , and the water drawn off from below .
The insulating water-bottle is a very efficient pieceof apparatus , and can be used in any weather inwhich it is possible for men to work without risk ofbeing was hed overboard it is not easily put out oforder except by being allowed to strike against theShip ’ s side . The continual blows of the messengertend to distort the striker plate , but this is easilyprevented by interposing a small piece of leatherperforated for the/ passage of the wire . The leathershould be fastened to the upper part of the frame bya few inches of string
,to prevent its floating up the
wire and checking the fall of the messenger .
42 THE WATERdepths and brought to the surface under lower pressurewill undergo a sensible lowering of temperature . Thematerials of which the water - bottle is made willSimilarly be cooled , and the total error m ay reach a largefraction of a degree . It is certainly possible to calculatethis error , but the rate at which the loss o f heat of thevarious parts ~ affects the temperature of the centralchamber and the thermometer cannot be estimatedaccurately . Ekman has drawn up a table in whichthe calculated corrections are reduced by one-halfin order to allow for this latter uncertainty (p .
I t will be seen that the error becomes larger as thetemperature and the depth increase , and belowmetres the insulating water-bottle Should not be used .
*
Reversing Water-Bottles and Thermometers.
The reversing thermometer is made so as actually toregister the temperature at any moment by the simpleprocess of turning it upside down ,
and,apart from faults
of construction,which unfortunately are difficult to
avoid , it gives extremely good results . It differsfrom an ordinary thermometer in having a constrictionand S - shaped dilatation immediately above the mainbulb , and in having a somewhat large secondary bulbat the upper end of the stem . The graduations arereversed so that the lowest temperature is markednear the tOp of the capillary portion . There are twowell-known models
,the original form,brought out by
For serial sarr/ip les from great dep ths ,
for which the
in su lating water -bottle is n ot adap ted , the han dy and in ex
p en sive “R ichard or
“Mon aco bottle , worked by am essenger ,
Shou ld p rove a u sefu l in strum en t , if strengthen ed an d p rovidedwith a p lace for a second thermom eter . It is a m od ificatio nof the large form u sed by B u chan an in H .M .S .
“Challenger
but has been som ewhat over- l ighte‘
n ed .
—ED .
EKMAN ’S CORRECTION TABLE 43
Sw O O O H N N m t j
- m m o m k oo ON O O O H
O O
06 N OO O O O H H N N M fi '
d‘ m l-ING R N OO OO O
O O O
m k kO I\
m v m m o o m m w o o o o o h w m n m m v v w
03
03
0404
06
0607
O8
08
09
09
09
I
OI
O1
01
1
1
I
1
21
21
2
05
05
07
O-o
-o O o
-o
‘O C
'O
-o C C O 0
8
O8
09
0909
1
0 o o
.O404
.O4
06
06
06
O6
O7
O7
O7
O7
08
08
08
‘M
‘
O
3
.03
‘
O3
.
05
.05
‘
O
5
'02
'02
‘OZ
‘
OZ
'02
‘
OZ
'02
O O O O O O O O O O O O O O O O O O O O O O U
N H O H N‘
M d' m KO N OO O O H N M fl
' m G N OO ON O
44 THE WATERNegretti and Zambra , of London , and a modifiedinstrument , made by Richter , of Berlin .
Fig . 8 shows the Negretti and Zambra instrumentas it is sent down ,
and Fig . 9 the thermometer byitself reversed . The thermometer is fixed in a framewhich can be turned over at will . On reversal eitherby a messenger (as in Fig . or by a propeller , themercury thread breaks at the constriction
, and fillsthe smal l bulb at the end of the capillary and also partof the capillary itself . I t is read in the reversedposition , and,
apart from certain corrections , to bementioned afterwards , the graduation on the stern
gives the desired temperature . The thermometerShould remain at the required depth for about fiveminutes to take the temperature of the water .
There are three sources of error,which all arise from
faults of construction . In the first place the wholeof the mercury in the main bulb m ay pass the constriction on reversal . This is not a common fault ,and thermometers subj ect to it should be discarded ,
though they m ay at times work well . Thermometerswhich show no signs o f this defect on reversing in thehand
,m ay fail when subj ected to the vibration caused
by hauling in from a great depth , especially in a roughsea . They should therefore be tested by reversingand tapping on a table . A second cause o f inaccuracyis due to the mercury which remains in the bulbexpanding past the constriction , when the therm om eter is hauled up through warmer layers , orbrought into a awarm er atmosphere . The S - shapeddilatation
,which differs slightly in the two models , is
intended to catch this mercury ,but it fails to do so at
times .
The third and most serious defect is that the mercurydoes not always part exactly at the constriction , and ,
REVERSING THERMOMETERS 45
in spite o f numerous experiments , it has so farproved impossible to remove it completely . Negretti
F IG . 7 .—S IX MAXI FIG . 8 .
—FRAME OF F IG . 9 .—R EVERSING
MUM A ND M I N IMUM R EVERSING THER THERMOMETER .THERMOMETER . N OMB TER .
(Figs . 8 and 9 by p erm ission of Messrs . Negretti and Zam bra . )
and Zambra trust entirely to the Shape and size of theconstriction
,while Richter provides an additional
. 46 THE WATERshort side-branch ending blindly . On reversal themercury
,
leaves this branch first , and then breaks atthe point where it j oins the main thread .
The temperature read off is not as a rule accurate,
but a correction must be applied to it in additionto those shown on the certificate . I f we cool a re
versing thermometer—say ,in water at 0°—reverse it
,
and then bring it into water at a higher temperature ,it will be seen that the temperature reading continuesto rise Slowly for some time . This is due to the ex
pan sion of the mercury in the capillary ; in fact , thecapillary and the small bulb are acting like an ordinarythermometer .
To calculate the correction we require to know(a) the temperature of the thermometer at the momentof reading (b) the kind of glass of which it is madeand (c) the volume , expressed in degrees of the stem ,
of the secondary bulb,and the portion of the stem
below the 0° graduation . This information is given inthe case of the thermometers made by Richter . Thetemperature at the moment of reading is shown by a
small auxiliary thermometer sealed up in the sameouter tube with the reversing thermometer . Thename or number of the glass is engraved on the stem ,
thus : J enaer 59 I I I or J enaer 1 6 I I I , and thethird quantity is also marked on the stem thus :“ Vol . or whatever the volume athappens to be . The apparent dilatation of mercuryin the glass 59 I I I is 3 3
16 6 ,in 1 6 I I I
3 316—6
.The cor
rection to be added to the reading of the reversingthermometer is
,in the case of 59 III , if vol .
Qfigfggfl i )
,where T is the temperature shown by
the reverser,and t that shown by the auxiliary . If
the air is warmer than the water , t will be greater thanT
,and the correction will be negative .
REVERSING THERMOMETERS 47
The calculation is made Similarly for another glassand Volume atThe Negretti and Zambra instrument is not pro
vided with an auxiliary thermometer,and the glass
used is not marked on the stem . It is hardly worthwhile to attempt to carry the correction to an extremedegree of accuracy , as
, even in the most closelydivided thermometers by this firm
,the gradua
tions are somewhat coarse , and the writer prefersto determine the correction directly by reversingat a known temperature , and observing the alteration on bringing it into water of a higher or lowertemperature (but see Addenda , p .
I t will be seen from what has been said abovethat the reversing thermometers are unreliable atthe best
,and they should always be used in pairs
to check one another . Their behaviour is verycapricious an instrument which has worked well foryears may suddenly , for no apparent reason , givereadings which are incorrect by several degrees , and
then , after an interval , may again act satisfactorily .
When an error of registering does occur it is generallyso large as to be obvious .
In the author ’s Opinion the Richter thermometer isthe better of the two models on account of its muchfiner and closer graduation , and the ease with whichthe correction is calculated . On the other hand
,it
is larger , heavier , and more costly than the N egrettiand Zambra model .In Spite of all its defects the reversing thermometer
is the only instrument available for depths greaterthan from 700metres to metres .
Reversing thermometers m ay be mounted either ina sim ple reversing frame or as part of a reversingwateribottle .
48 THE WATERThe reversing frame is actuated by a propeller or a
messenger , and should be made to carry‘ two thermom eters and to fit anywhere on the wire , so that astring of instruments can be used simultaneously . Thepropeller is somewhat unreliable
,and not infrequently
fails altogether . I t is fixed on a finely threaded screw,
and is so arranged that on the way down it revolvestill it butts against a stop . On hauling up
,the direc
tion of rotation is reversed , and the screw releases a
trigger which permits the frame to fall over . Thedistance through which the frame must be hauled upbefore reversal takes place is uncertain ; this is of noconsequence in great depths where the temperaturechanges Slowly , but it Vitiates the results in theupper highly-heated layers . The messenger is muchmore reliable , and its sole defect is the time requiredfor it to fall through great depths . In such a casethe Shock of its striking the frame cannot be felt
,
and a suitable interval must be allowed,which can be
determined in shallower depths . If a string of therm om eters is used ,
a fitting is provided by means ofwhich each frame , as it reverses
,releases a messenger
hanging below it , which actuates the next frame .
Reversing water-bottles are made so as to carrythermometers and at the same time to collect a sampleof water from any depth . The only form of whichthe writer has had practical experience * consistsessentially of a brass tube , tinned inside , and mountedinside a rectangular brass frame on two pivots . A
hinged lid with rubber washers is fitted to each end ,
and these lids are also connected to eccentricallypivoted arms . On reversal the arms cause the lids toclose firmly . Made to fi t anywhere on the line , it isspecially adapted for serial observation s and greatdepths .
Ekm an Publ . de C ircon stan ce , No . 2 3 .
THE WATERA form o f insulating thermometer which m ay be
o f use in some cases is an instrument of the ordinaryform
,the bulb of which is surrounded by a thick mass of
a badly conducting material—india- rubber , for instance .
Such a thermometer will take some hours to come tothe temperature of the surrounding water
,and will
take a similar time to lose this temperature on haulingup into the air . I f the thermometer be hung j ustClear of the bottom from , for instance , a lightship ,
and be hauled up at intervals of some hours for reading , it is possible that the records will give someindication of the changes below . Under certainconditions , where there is a very small daily range , thereadings may be of real value .
Methods of Using Water-Bottles, etc .
All modern instruments are made for use on wireand not on hemp rope , and in most cases only for astranded flexible wire of a diameter of from 2 to 4millimetres . The single wire is not now generally used
,
on account of its great liability to kink and break .
The stranded wire is much safer, but of course offersmore resistance to the water . The writer has usedsuccessfully a wire rope of about 2 -2 millimetresdiameter with a breaking strain of 400 pounds .
through the p o in ts p lotted is susp ect, and shou ld be re
p eated . This m ethod will also Show any cr itical hor izonat which the change of tem perature is sudden ; round thishor izon m ore n um erou s observation s shou ld be taken at , say ,
5 0 fathom s interval . At each observation m ark the n umberof the therm om eter used this will soon Show up an unre l iableinstrum en t . These therm om eters are m ade for Adm iraltyu se with an extra large scale , which adm its of very c loseread ings , and is to b e recomm ended—ED .
WATER-BOTTLES 3 1
VVater-bottles may be used either from a davit or
from a swinging boom . The latter arrangementrequires at least one extra hand to work it , but it isfar preferable to the davit , and makes work possiblein decidedly rough weather . The depths at whichobservations should be made cannot be laid downbeforehand . In areas which have been previouslyexamined the records of the earlier observationsgive considerable help . In unknown waters one canonly go on the principle that the chief obj ect is todetermine accurately the position of the dividinglines between layers of different temperature and
sal inity . As the latter can only be determined onshore , the number of observations should always erron the s ide of excess .
As a rough guide for working in unknown watersdepths of o , 2 , 5 ,
10, 1 5 , 20, 25 , 3 7 , 50,100, 200, 300
fathoms , etc . , m ay be recommended . When thedepth of water does not exceed 200 fathoms
,the
surface layers are of great importance . In the openocean , on the other hand , fewer observations near thesurface m ay suffice , if this should be necessary ,
inorder to allow time for the more complete examinationof the lower levels .
The distance apart at which the stations should beplaced will also vary according to the locality . Onthe Continental plateau to the north and west ‘ ofEurope they may be spaced as closely as twenty mileswith advantage , but in deeper waters the programmecan only be decided on after a careful considerationof the time available and the records of previousexpeditions .
With regard to surface samples the case is somewhatdifferent , as it is not necessary to stop the ship . In theEnglish Channel and in the Bay of Biscay the writer
52 THE WATERhas made it a rule to take a surface sample every tenmiles but , on the other hand ,
an Atlantic liner coulddo very valuable work by arranging for an Observationevery four hours .
Chemical and Physical Examination .
Sea water consists of a solution of various saltsdissolved in pure water . The ratio these salts bear toone another is generally so constant that , for mostoceanographical purposes , we m ay consider that itremains unchanged while the total amount presentvaries . It follows , therefore , that if we determine one ,say the chlorine , we can calculate the total weight ofall, and also the specific gravity . Tables have beendrawn up from time to time to enable this to be donequickly ; the most recent are Knudsen
’
s,which were
calculated on the basis o f a number of careful exp eriments for the International Council for the Explorationof the Sea , and as it is of the greatest importance thatallmodern hydrographical researches should be strictlycomparable with one another
,the methods and stan
dards of the Council Should be followed accurately . Thework of analysis can only be carried out by , or underthe supervision of
,a skilled chemist . Its details are
too elaborate to find a place in this elementary handbook
,but the Society will be glad to advise in the
matter .
A sea water can also be examined by direct determination of its density at an exactly known tem
perature . I t should be stated here that the ordinaryhydrometer of partial immersion , in which a portionof the stem appears above water , is absolutely uselessfor modern work , and Should be discarded . Thechief cause of its want o f reliability is the great dis
SPECIFIC GRAVITY TESTS 53
turban ce caused by the slightest trace of dirt eitheron the stem or on the surface of the water .
There are three other methods of determining thespecific gravity which give accurate results . Onem ay weigh a known volume of water in a pyknometeror one may weigh a body of known weight and volumein the sample of water ; or , finally
,one may use the
total immersion hydrometer . Of the first two thepyknometer method is the better , but both requirean accurate balance and weights . The total Immersionhydrometer is shaped like an ordinary hydrometer,with an ungraduated stem of about 3, inch or 53 inchlong . To use it
,it is loaded with small platinum ring
Shaped weights , which are dropped on to the neck oron to a platinum hook fastened to it
,until it floats
in m idwater . The system is then of the same specificgravity as the water . I t is very accurate , and oncethe apparatus has been standardized the balance isno longer required
,and the whole outfit is easily port
able . The hydrometer and pyknometers should bemade with the same accuracy and care , as regardsthe quality of the glass , as an accurate thermometer ,in order to avoid uncertain changes of volume .
In all specific gravity determinations the greatestdifficulty is keeping a constant and accurately knowntemperature throughout . The writer has found anOstwald thermostat of great value in such work .
Current Measurement.For the measurement of currents below the surface
the Ekman meter is probably the most convenientapparatus (Fig . It consists of a hollow spindleturning freely by means of ball bearings on a wirepassing through its centre , and bears on one side two
54 THE WATERvanes A , inclined at a small angle to one another
,
and on the other a framework carrying devices forrecording the velocity and direction . The velocity ismeasured by the revolutions of the propeller B
,which
turns on centres supported in agate cups,and is con
n ected by gear wheels with the pointers moving on thedials on the cover of the box F . These pointers movestiffly on their pivots
,and can be set to zero before
each observation . The velocity of the current iscalculated from the number of revolutions in a giventime by a formula which must be determined exp eri
mentally for each instrument .
Beneath the box F is a compass,which can be
quickly removed and replaced,and is kept in position
by the thumb - screw shown below it . The needle isheavy , and the arms are inclined downwards , and
one arm is deeply grooved on its upper surface . Inthe box F there is a store of small shot , which arereleased one by one by the rotation of the propeller ,and fall through a funnel on to the centre of theneedle
,whence they run down the grooved arm on to
the compass card . The latter is divided by raisedpartitions
,and the shot falls into the compartment
below the end of the arm ,and so records the direction
in which the apparatus was pointing at the moment .
The instrument which the writer has used has a carddivided at every 10 degrees , in such a way as to recordthe direction from which the current comes , and notthat in which it goes .
The meter is started and stopped by means ofmessengers . When it is being lowered to the requireddepth
,the messenger C is not on the wire , and the
arm D is more nearly vertical than shown in thedrawing . The other end , E . is therefore slightlyraised
,and the proj ection on the propeller blade butts
CURRENT METERS 55
against it,so that the apparatus is locked . To release
the propeller,the first messenger C is allowed to slide
down the wire it forces D outwards into the positionShown in the figure the slot in E is now opposite to
0 q
the proj ections , and the mechanism is freed . Aftera measured interval a second messenger is sent downthis is larger than the first , and hollowed out belowso as to pass over it . It forces D still farther outwards
,
and again locks the propeller . The direction and
56 THE WATERvelocity of the current then can be read off from themean position of the Shots in the compass card and thenumber of revolutions shown on the dial .The wire should be as fine as possible to avoid
stray, and if of steel any deviation which it may cause
in the compass should be determined and allowed for .The sinker may weigh from 10 pounds upwards ,according to the strength of the current . Withcurrents of a knot an hour and over , in depths greaterthan thirty fathoms
,the writer has found that it was
not possible to feel and time the arrival of the m es
sengers on account of the vibration of the wire . Insuch a case one must determine the time of fall of eachmessenger for various depths and plot the result on acurve . It will be seen that they soon reach a constantvelocity , so that the time may be calculated from thedepth .
The Ekm an meter,of course
,demands some fixed
point , such as an anchored boat or ship,from which
to work it , and in rough weather the velocities are notrecorded accurately ; under suitable conditions , however , it is very easy to use ,
and the results agree wellamong themselves . When t ested at the surface froma boat , especially if the current is slow ,
it is seen towave from side to side continually ,
but this app earsto be due to eddies below the surface in currents ofover a quarter of a knot per hour it points constantlyin one direction .
The interval during which the propeller should beallowed to rotate depends on the strength of thecurrent when this is not known approximately , fouror five minutes may be tried in the first instance .
Additional apparatus has also been made by meansof which it is possible to work in rough weather froma ship that is not anchored
,but the writer has not had
58 THE WATERwinds which drive the surface water along . Theseterms , however , are not always accurately used .
There is yet a third type of current,which either
upwells from below or Sinks from above,its movement
being determined by the relations which its temperature and salinity bear to those of the adjacent water .
Surface Currents.
I f we begin with the surface movements of theATLANTIC OCEAN—as being better known than theothers , and Simpler in so far as it is not studded withislands like the Pacific , nor subj ect to monsoonal disturban ce like the Indian—themost prominent is the GulfStream , The North Equatorial Drift and the northwesterly arm of the South Equatorial Drift (Chart V. ,
p . hurried along in the first instance by their respective trade winds
,strike ultimately on the Windward
Islands while a part of their water Skirts the outsideof theWest Indian chain
,in a north-westerly direction ,
much passes into the Caribbean Sea, and thence , ina highly heated condition
,through the Straits of
Yucatan into the Gulf of Mexico at anything from1 5 to 70 knots a day . The water thus driven into thegulf , supplemented by the great volume of the Mississippi , forms a hydrostatic reservoir , the level ofwhich IS something like 40 inches above mean sea- levelat Sandy Hook . Having practically only one outlet ,the Straits of Florida , it rushes through them witha mean annual temperature of over 80° F and at a
rate of 20 to 100 knots a day ,passes over the Blake
plateau which it sweeps clean,and debouches into
the main ocean about 30°N . ,where it is j oined by
that branch which skirted the outside of the WestIndian Islands . Here it is diverted , chiefly by preva
SURFACE CURRENTS 59
lent winds,to a north- easterly direction . This diver
sion m ay be helped by the pressure of the continuationof the cold Labrador Current, a much weaker current ,composed of water of very low temperature and salinity ,
derived from the melted ice and snow of the Arcticregions as far north as Baffin Bay . About 50
°N .
much of this current turns from south- east to aneasterly
,and eventually north-easterly , direction but
a part swings round Labrador to south-west , and skirtsthe north coasts of the eastern United States , gr eatlylowering their temperature . To some extent , however ,the cold water in this region is attributable to up
welling caused by the pull of the Gulf Stream . Theboundary between the hot and cold waters of the GulfStream and Labrador Current swings north and south ,
according to the predominant winds ; it is said to beso Sharp sometimes that a Ship ’ s bow may be ingreen cold water of arctic origin
,while her stern is
in warm blue water from the Gulf .The Gulf Stream gradually assumes a more easterly
trend . I t has been calculated that at about 40°W . it
has lost the velocity and temperature which it s wateracquired in the Gulf . This water still continues ,however , to travel east , but the driving power now isnot the original head of water
,but the prevailing
south-west winds of this region . It is therefore nolonger a stream
,but is better termed the North
Atlantic Drift. Between 40° W. and 20
° W.,the pull
of those winds round the high-pressure area,which
culminate in the trade winds,draw off much surface
water past the Azores in a south- easterly and southerlydirection . But the main axis of the drift
,being outside
their influence , passes north- east,striking the Faeroe
and Shetland I slands . I ts influence is well Shown onboth isotherms and isohalines (Charts I I I . and as
60 THE WATERfar as the triangle between Norway , Spitsbergen and
Nova Zembla . In this region the weight of this water ,due to its high salinity causes it to sink in spite of itstemperature
,and all traces of it are gradually lost .
The water shed off from the main drift in a southeasterly direction about the Azores is mainly drivenagain by the trade winds into the North EquatorialDrift, which runs from east to west about 10
° N .
and so the cycle of the North Atlantic begins anew .
A branch, however ; skirts the Guinea coast , and - isknown as the North Africa Current. It probably findsits way into the South Equatorial current .In the South Atlantic the south- east trades drive
water along a South Equatorial Drift from east to'
west between 0°and 10
°S . Impinging on Brazil , a
part of this turns north-west to j oin the North Equatorial , as we have seen the rest turns south-west as theBrazil Current, sending offwater south and south- eastinto the rotatory circulation round the high- pressurearea . But the currents are here complicated by thearrival of antarctic waters . In the Southern Oceanbetween 40
°S . and 60
°S . , there is a great Easterly
Antarctic Drift of cold Water round the Pole , duelargely to the prevalent winds RoaringThe deep southward proj ection of South Americaseems to darn this to some extent , and as soon as thedri ft is clear of the straits between the Horn and theAntarctic continent (compare Fig . a branch spreadsup northwards as the Falkland Islands Currents, corresponding to the Labrador Current in the northernhalf of the Atlantic . This cold water meeting thewarm Brazil Current off Rio de la Plato produces amost extraordinary effect on the isotherms (ChartThe resultant waters get an easterly trend acrossthe ocean . Before reaching the longitude of the
SURFACE CURRENTS 61
Cape of Good Hope , they send a branch north , whichis probably attributable partly to the pull of thetrade winds , partly to a resistent current in theopposite direction coming from the Indian Ocean .
This branch contributes to the cold Benguela Currentalong the West A frican coast , of which a large partseems due to an upwelling of cold water from below ,
owing to water being drawn off the surface by thetrade winds . This brings us back to our starting- pointin the South Equatorial Current . Between the Northand South Equatorial Currents is an ill -defined backwater , the ‘ Counter-Equatorial Current, with a sloweasterly trend .
We may now turn to the PACIFIC OCEAN. In thisthe simple currents of the diagram (Fig . 5 ) are confused ,
and their strength frittered away,by the numerous
islands of the middle and western regions of this ocean .
But we can recognize as clearly marked the North‘
Equatorial Drift, northing and easting to form theJapan Stream (Kuro Shiwo) and North Pacific Drift ;the Kamschatka Current, corresponding to the LabradorCurrent of the Atlantic and the return of water fromthe eastern Side of the high-pressure area by the pullof the north- eastern trades into the North Equatorial
,
in the shape of the Californian and Mexican Currents.
In the south half of this ocean that br anch of the SouthEquatorial Drift, which corresponds to the BrazilCurrent , forms the Australian Current, pressed eastwardby a branch of the Easterly Antarctic Drift betweenTasmania and New Zealand . Before the Horn isreached , a northerly branch of this contributes to theHumboldt and Peru Currents, supplemented by anupwelling as in the case of the Benguela Current . A
well-marked Counter-Equatorial Current characterizesthis ocean .
62 THE WATERIn the INDIAN OCEAN, or half ocean as it m ay
be termed , the same general circulation is only clearlymarked north of the Equator during the south-westmonsoon (May to September) . Off the Cape of GoodHope the Mozambique Current, which corresponds tothe Brazil Current o f the Atlantic , is barred by theEasterly Antarctic Drift to an extent which producesa remarkable recurving of the former from a southwesterly to an eas terly direction . To the constantconflict between these hot and cold bodies of wateroff Cape Agulhas are attributable the well-knownfogs of this area .
Movements of Deeper Water.The rain , hail , and snow precipitated in vast quantityon the Antarctic Continent , melting to some extentin the summer , give rise to a water of very low salinity ,
but also of so low a temperature that it sinks belowthe warmer salter water of more northern origin
,
Chiefly from this source appears to be supplied the verycold bottom water, which lies on the bed of all deepoceans . There is some reason to believe that a lesserquantity is derived from Arctic melting . Conse
quently it is nearly always true that the deeper onegoes in the great oceans , the colder is the water . Thus ,for example , the mean temperature of all oceans at
fathoms was calculated by Dr . Buchan as
3 5 2° F . (1 6
° Hence,whenever there is an
upwelling of water to the surface , due to water beingdrawn away from the surface by the pull of windsa phenomena which is particularly observable on thewest coasts of all continents—the water thus upwelling is comparatively cold for its latitude , and oflow salinity (compare the isohalin es on the west of
CLOSED SEAS 63
British Columbia , Chili , Australia ,and the Cape) .
In addition to these upwellings alongshore , it has beensuggested that they also occur at certain points inthe Open ocean . There is also some evidence for theexistence of horizontal mid-water currents, in a direction the reverse of that of the currents immediatelyabove them . Observations on this question are
sorely needed .
Before leaving the Subj ect , a word must be said onclosed seas. The classic instance of these is theMediterranean this includes two deep basins of morethan fathoms
,but its entrance at the Straits
of Gibraltar is barred by a ridge of 60 to 1 30 fathomsin depth . Consequently, the cold bottom water ofpolar origin never penetrates into it , and the differencein temperature between the surface and the bottom iscompar atively slight . Mediterranean water is thr oughout warm and of high salinity . A surface currentfrom Atlan tic to Mediterranean through the Straitsis compensated by an undercurrent in the reversedirection the water which thus escapes into the openAtlantic spreads , and sinks by reason of its high salinity ,
carrying its high temperature to quite unusual depths .
An instance of a cold closed sea is furnished by theFaeroe Channel , shut off from the main Atlantic bythe Wyville Thomson Ridge .
While exact observations on currents , and especiallyon mid-water currents , are much needed
,the usual
methods for their determ inatlon (by buoys , log- Ships,
etc . ) are so rough and inexact that they cannotusefully be employed by any but skilled hands . Ofmore elaborate machines the Ekman current meter(p . 55 ) has proved very useful in shallow waters ,and a more heavily built pattern could no doubt bemade to do deeper work . But for accurate measure
64 THE WATERment , the ship must be anchored bow and stern
,as
even her yawing round a Single cable will seriously affectthe record . The Pillsbury meter
,as improved by the
British Hydrographic Office,is a beautiful machine
,
but costly, and rather cumbrous to work . I t couldprobably be somewhat simplified and lightened . A
most interesting and practically untouched field liesopen to any yachtsman of ingenuity
,who will attack
the problem of'
m id-water currents , which the ordinaryShip , whether naval or mercantile , has no time evento consider .
As to the‘
daily movements of ocean water , thesubj ect of the theory of tides is rather for the astronomer and mathematician than for the oceanographer .It will be enough to say here that if a stay of any lengthbe made in an out-of- the-way port or harbour , dailyaccurate measurements of tidal movement would befound useful to the naval authorities
,and of real value .
A tide-pole , well guyed , marked in feet and decimals ,will do all that is necessary . A board carrying a lightscale- rod , floating freely in a square tube of four planksknocked together
,with holes in the bottom to admit
the water , will be found easier to read , as avoiding thewash of the waves . Both these require frequent reading
,if the observations are to be of real value ; but
regular tide-gauges can be purchased , which recordthe rise and fall automatically by curves on squaredpaper .
66 THE SHOREin the sand or under rocks , and fish have departed fordeeper waters . Thunder and lightning
,an d even
changes of barometric pressure,make themselves felt
,
animals seeming scarce before an approaching cyclone .
There is also a regular periodicity between night andday ; many animals visit the shallow waters duringthe night alone
,an d some o f the sedentary organisms
only unfold their heads for feeding purposes in darkness . Again , t ides should be observed ,
for it is commonto see masses of apparently lifeless rock become coveredwith flowers formed by anemones
,worms
,etc .
, as soonas the first flow of the flood reaches them sand- livinganimals
,too , renew their activity and commence to
pile up afresh their mounds of sand . These resultsmay be due to the cooler waters of the Open ocean
,but
observation s on these matters are urgently needed . A
watch,a thermometer , and a notebook should be the
naturalist ’ s invariable companions on every stroll,
while a good barometer Should hang in his ship or tent .
When any land is approached , its contours should becarefully noted , particularly its valleys an d slopes , Sincethe sea-bottom is bound , for some considerable distanceoutwards
,to be formed of the rock of which the land is
composed,perhaps masked by a superficial deposit o f
sand or mud . Specimens of rock should always be takenand carefully labelled , even before being dropped intothe satchel . Its formation must , to a l imited degree ,be considered—whether it is volcanic
,or has been
formed by other agencies how it has been cut up intoits present
,perhaps fantastic , shapes what results
in its contours are due to rain , to wind , to heat , and
to cold,and
,lastly
,to the influence of plants , and, in
some few cases,of animals . This will be found to be
a delightful study , as it gives a new charm to thescenery
,and it is only by its means that the topography
ALTERATIONS OF LEVEL 67
of the island or coast,particularly in connection with
its submarine Slopes , can be understood . Certaineffects recur on many lands , and the voyager soonbegins to recognize the nature of their rocks long befo rehe actually reaches their shores . Observations onchange of level are of importance , but difficult to make .
The earth has by no means a rigid or unbreakablecrust
,and the present distribution of land and water
is generally considered to be due to the alterationswhich have constantly been taking place in its surfacein past geological periods . The world must not beconsidered as if these movements have now stepped .
Indeed,their cessation is directly negatived by the
existence of volcanic eruptions and earthquakes .Some movements , especially those associated withvolcanoes
,are very local
,but others affect wide areas ,
such as the one which appears at the present timeto be slowly elevating the North of Scandinavia ; thisfinds its balance in a general depression of the South ofEngland , there being thus a regular tilting oVer somethousands of miles . This movement
,fortunately
,is
a slow one (as all large alterations of level probablywere) , and has little effect on contemporary historybut many local upheavals and subsidences must havetaken place with great rapidity . There are manylines and points of weakness in the earth ’s crust beneath the sea
,and to the subterranean forces under
these we owe the existence of most of our oceanicislands . The examination of the earth ’s crust beneaththe sea is impossible
,so that special attention must
be paid to all signs of change of level round coasts onoceanic islands . Elevation—that is
,the emergence of
formerly submerged land—is shown by marine depositson the hill- slopes , which in the tropics are generallylargely calcareous in nature . Any appearances of
68 THE SHOREhorizontal terraces above the shore Should be at onceinvestigated . When examined , they are found either tobe shelves , cut out of the rock below by wave action ,
often strewn with pebbles and marine remains or tobe artificial formations of limestone
,implanted on the
rocky Slope below for a foundation . I f,as on many
islands , there are series of these terraces , specimens ofthe rocks of each should be carefully collected at
different elevations their heights above sea- levelShould be ascertained (a good pocket aneroid withscale of heights is useful) and their surface , appearance , and extent should be noted down ,
especially theexistence or non - existence of caves . Often the slopesof the land are so steep and the rainfall is so abundantthat only traces of elevated rocks are found at the sidesof the valleys , and sometimes even these are lost . Yetevidence of elevation may be found in the existenceof isolated caves and overhanging rocks
,or even scat
tered marine shells .
All the above land form ations,wherever found
,Should
be compared with the present action of the sea on thesame coasts . This latter has its own importance aswell
,and should be studied all round the land—to
windward and to leeward , where the current directlystrikes on the land to pass out in an undercurrentwhich curls round its points
,where it merely Sweeps
the capes as it passes by ,and where it curls round them
forming eddies . The action of the sea on the rocksof the shore is important
,and the rocks themselves
should be examined,to see how far they are protected
by corals, Lithothamn ia (massive red and white en
crusting calcareous plants) , seaweeds , barnacles , and
other organisms . Masses of rock , small islets near themain mass of land ,
require examination in order to seeto what causes they owe their present isolation . The
SUBSIDENCE 69
sand of sandy beaches or points should be sampled ,
so as to ascertain how far it is formed by the breakingdown of the rock
,an d how far it consists of the re
mains of organisms piled up by the waves . From theinhabitants we often obtain valuable information ,
positive measures of the loss or gain we frequentlyrequire to learn from them whether we are examiningbeaches which are permanent
,or which shift according
to the variation of seasons or perchance the monsoons .
In the course of such work we may get indicationsthat land
,formerly dry
,has sunk below the sea ;
but this is more difficult to prove . The sea often cutsa flat at the low- tide level into the land if the latte rbe stationary
,an d the breadth of the flat m ay give
us an indication of the period of time for which it has
so remained ; such a terrace , however , m ay be com
pletely obliterated by the tropical rainfall . The ab
sence of a terrace an d of loose masses of rock off a steep
glacis or slope may well arouse in u s suspicions of theexistence of subsidence
,an d we shall be tempted at
low tide to row round,to observe whether signs of
aerial weathering are visible on the submerged partsof the rocks
,an d perchance to carry out a few sound
ings . Pillars,etc .
,of any permanency
,such as exist
in the Bay Of Naples,are unlikely to have been erected
by the shore on any land we visit,and it is only by
exact survey and careful studv of the topography ofthe slope that we can arrive at any conclusions on thematter . A rugged coast
,deep bays or fiords
,a fairly
constant slope without steeps to a few hundredfathoms or so
,might indicate subsidence ; but such
observations belong rather to the HydrographicalOffices of the Admiralties—they are scarcely withinthe compass or time of the visiting naturalist . A closeline of soundings out from the shore (made
,if n eces
79 THE SHOREsary
,with a weighted an d measured codline
,and
based on the angles obtained by the sextant betweenthree posts fixed 100 or 200 yards apart on the Shore)is often a most u seful supplement to existing charts ,and gives information of great value . I t would at
least show the existence of submerged terraces,if
present , and they are the best proof of subsidence inany region .
Whatever of marine life the naturalist collects in thetropics is almost sure to be of interest and value . I fhe has little time at his disposal
,he will probably be
able to get or to give to others a good idea of themarine life of the locality by Simply walking along theShore , or visiting some outgrowing spit of sand ,
an d
dropping into a canvas bag everything which s eems tohim to be of organic formation , n ot forgetting to include also a sample of the sand itself . He m ay searchalso for the numerous animals found between thetide-marks
,employing a native or two with buckets
in which the larger beasts are placed , while he himselfcarries a satchel with two or three dozen tubes ofdifferent sizes
,into which he puts the smaller beasts
,
corking them up in sea water they can then be transferred to the preper killing and preserving fluids onhis return to his ship or tent . Let him carry with himas a walking- stick a small crow—bar to turn over massesof rock
,while one of his boys has a hand-net of
fine mesh coarse forceps should be looped on his belt .
A l ittle of such collecting is valuable,to give him an
idea o f the shore -beasts as a whole an d of their workin protecting or destroying the land . But much ofthe action of the sea and its organisms goes on belowtide - level . This can only be satisfactorily ascertainedby dredging or trawling from a ship or boat . If thisis impossible
,let the naturalist get some old rope- ends ,
WORK AT ANCHOR 7 1
and,by unravelling the strands of the hemp , make
swabs such as are used for drying up the deck . Theseswung over the stern of his vessel on to the bottom ,
with two or three fathoms of rope to spare , if takenup and cleaned every twelve hours or so , will Oftenbring up a great variety of living organisms , pieces ofrock with a couple of dozen different kinds of sedentaryanimals attached to them , numerous Crustacea , starfishes
,worms
,and other forms . A couple of plankton
nets floating out from the ship at the same time , inone- third and two- thirds the depth of the anchorage ,will indicate to him the floating fauna
,on which the
animals of the bottom so largely feed . When theanchor is raised , mud or sand is often found clingingto it
,and a good sample should certainly be secured
and dried ,after putting any l iving organisms that may
be found into some preserving fluid . A washing infresh water and treatment with a little weak spirit ,which otherwise would have been cast away
,will
prevent any obj ectionable smell from the sand whenin process of drying .
By such methods as the above the naturalist willobtain a general View of the life of the coast which heis visiting . He may even attain an idea of the interrelations of that life with its environment thetopographical and physical conditions of the region .
He may proceed farther, an d see how the animals andplants interact with one another how the freelymoving forms take refuge within the branches of thesedentary organisms ; how the struggle continuallygoes on between the sedentary animals and plants ;and , lastly ,
how both animals and plants in their vegetative phases of growth adapt themselves to theirenvironmen ts . Such a study , particularlyof the lat terpoints, is of the greatest value to the worker on syste
72 THE SHOREmatic zoology at home
,and has a peculiar interest of
its own . It has seldom been systematically attemptedon a proper basis . A small area—a single pool
,per
chance—should be intensively studied in its everyaspect . It Should be sounded and measured ; itstemperature should be taken under different condition s the effect of the ebb and flow of the tide shouldbe noted ; a plan should be drawn of the position ofeach single animal and plant and all notes should bewritten with the pool at one ’s feet . Whether theindividual animals and plants are known to one ornot does not matter , because a sample of each has tobe taken . In the case of sedentary animals , theupper and lower surfaces , as well as those againstan d remote from any tidal or o ther currents whichenter the pool
,should be carefully marked . Nothing
is too small to be recorded,
and the more thoroughly the work is carried out
,the greater will be its
value .
Such collections from a single pool are ,however , of
little direct use to the systematist at home . They are
too scrappy by far for his purposes,and he cannot from
them venture to attempt any of those broader deduction s on the distribution of plant and animal lifewhich make much of his work of interest . Somenaturalists
,also
,are more disposed to collect and
accumulate specimens of different forms of life , likingto wander over wide areas . To them we say , let themcollect by all means
,but confine their attention to
one or a few classes of animals,or to plants alone ,
unless they have at their disposal at least three orfour months at each place
,and can set up perm anent
laboratories on shore,conveniently arranged . In
giving suggestions as to what groups to select or whatgroups would be of most value to the marine biologist ,
74 THE SHOREthe massive calcareous forms , as they vary so greatlywith environment .
O f groups o f free- living animals on tropic shores,
the fishes, Crustacea ,
starfishes (except the Crinoids) ,and Mollusca ,
do not vary greatly in genera and speciesover each of the two great geographical ocean areas
,
the Atlantic and the Indo-Pacific . They are alsofairly well known
,having always presented great
attractions to the collector , from their number and
beauty,and from the ease with which they can be pre
served by being simply dropped into 90 per cent .
spirit ; they dilute this down to about 60 per cent .
by the time the tank or bottle is full . Crustacea and
starfishes should always be wrapped in cloth if theyare to be placed with many other animals in a largereceptacle
,an d a preliminary soaking in dirty spirit
of about 40 per cent . prevents Crustacea from gettingbrittle and soft sea-urchins from getting distorted .
The sea- Slugs , or Holothurians , should be inj ected bymouth and by anus with 90 per cent . spirit
,using a
syringe . Numbers of these groups of animals m ay befound in pools , in the branches of corals which requireto be broken up to liberate them , in weeds , and understones they m ay be caught with the hands or by thenet . Large forceps are advisable for spiny sea
urchins , and digging in sand will yield a few bivalves
(Lamellibranchs) and Holothurians (trepangs) . A
few pence—or pieces of tobacco (sticks , twenty- six tothe pound
,price tenpence to a shilling)—j udiciously
expended among the natives,will bring in many of the
larger forms more difficult to catch . Heaps o f stoneand corals
,baited with coconut scraped up and
mixed with the ink of the cuttle-fish (or with poundedup land- crabs) , piled on sandy flats
,covered with
2 or 3 feet o f water at low tide,were responsible for
ANIMALS 75
upwards of eighty different species of fish fromRotuma
,
*aswell as for a large variety of Crustacea and
other free- living animals . The animals,after a few
days,find out such heaps
,an d make them their homes ,
going out with the flood in search of food,but returning
with the ebb . They are then easily caught in a largebasket of palm - leaves
,which is kept open by a few
masses of branching coral,an d is placed
,mouth open ,
in the Opposite end of the heap to that which the collector is turning back . Some of the brilliantly colouredfish resist such a device
,and the author knows no way
of catching them save by a bare fish-hook of smallsize
,smeared with cuttle-fish ink
,which has already
been mixed with patchouli or other strong- smellingscent . He has found this efficacious in the crevicesof coral reefs
,the line being swept in and out by the
tide . As to the advisability of the inexperienced collector
,who does not himself know the orders and
divisions of these groups,and is not especially interested
in them,gathering them up
,the author of this article
expresses no further opinion . The Nudibranchs andIsopleura , the smallest Crustaceans , and the minuteshells from the sand
,will be most profitable ; while
such Crinoids as m ay be found Should certainly bekept . As a matter of actual experience , two - thirdsof the time even of a , train ed collector , desirous ofsecuring all forms of life on the shore , will be occupiedin catching and preserving the larger members of theseorders . The breaking up by the hand of masses ofthe more mossy seaweeds into a bottle , the larger fragments being picked out
,often yields an abundance of
small Crustacea and worms . The result is a dirty
Of 108 sp ec ies of fish co llected by the author from thisisland ’
s shores all were kn own , an d on ly abou t 2 p er c en t . of
the sp ec ies from o the r is lan d group s were n ew .
76 THE SHORElooking mess , with much sediment , in which are theanimals it may be preserved by adding one-twentiethof its volume of ordinary commercial formic aldehyde
(a 40per cent . solution, see p . leaving the sorting
out of the different animals to be done in the laboratoryof a colder climate .
While individual genera of the last groups of animalsare adapted to almost every environment , most othergroups of free- living forms are adapted to some particular environment . Thus Amphioxus of differentgenera all live in sand , though they pass their larvalexistence as pelagic animals . Such sand must be clean
(sharp ,as it is termed) , an d preferably in such a position
that it is slightly stirred by the rise and fall of everytide . Even if present , Amphioxus is generally local ,but where it occurs it is enormously abundant ; largenumbers may be readily obtained by sifting the sandthrough one or a series of sieves of different meshfitted into one another
,which are held while being
shaken just submerged in the sea water . Equallysand- loving are Balanoglossus and its allies , but theyprefer either rather dirty sand—flats , into which theyburrow (throwing up great mole-heap- like mounds ofthe sand which has passed through their bodies forfood) , or else the rather shallow accumulations of sandunder or in the crevices of stones
,where they get out
of the reach of the other forms of life which might preyon them . A SlIght smell like cyanide or prussicacid in the sand is a sure sign of their presence , whilea smell of sulphuretted hydrogen (rotten eggs) may .
practically speakin g , be taken to indicate the absenceof most forms of animal l ife . The author ’s receipt forthe sand- living forms is to find a flat of sand overlyinga bed of rock a foot or two below . The collector willsee at once if there are any mounds, and,
if so , he wi ll
ANIMALS 77
probably dig with success , using an y spade or shovel ,but if the sand is deep he m ay follow the animal
’sburrow down into the sand till he himself is completelysubmerged
,and meet with no success however long he
tries . Both of these groups of an imals are of greatinterest for their anatomy ,
an d plenty of specimensshould be obtained if they are present . The Balano
glossids should be kept in the shade in basin s of seawater
,changed every three or four hours during the
daytime for twelve to twenty- four hours,until they shed
the sand of which their bodies are full . The membersof both groups may be killed and hardened in corrosive sublimate or other preserving agent , as describedelsewhere or
,failing these , may be dropped into 30per
cent . Spirit for one hour , 50per cent . for the same time,
and then kept permanently in 70 per cent . spirit . Thelatter for Balan oglossids should be changed at leasttwice
,as they possess in their bodies some substance
which in the tropical heat acts on the spirit,tending to
decompose it,their own bodies disintegrating at the
same time .
Worms (spin y Chaetopoda and Sipunculoids) arefound in almost the same localities as the last groups
,
and many should be secured while searching forBalan oglossids, the mounds of some of them ,
particularly the Sipunculoids , being diffi cult to distinguishfrom those of Balan oglossids . In addition we havemany Chaetopods which form tubes on rocks
,and mem
bers of both Chmtopods and Sipunculoids are amongthe most important of boring organisms . There is noroyal road to success in collecting
,save only hard work .
It is well to half fill one ’s boat , or send one ’s bucketsashore
,full of masses of rotten calcareous rock
,of dead
and living corals,and of Lithothamn ia . Then when
the rise of the tide makes further work in the sea
78 THE SHOREimpossible
,we sit down with hammer an d Chisels
breakin g up these masses into fragments,an d carefully
chipping out each animal we see,to secure it intact .
We will have all around us basins , for our catch will bea varied one . There will be Crustacea
,Mollusca of all
kinds,flat worms (Turbellaria) , an d an odd Nemertean
perchance in the crannies of the rock masses we shallalso find growing there a great variety of sedentaryanimals
,some of which we shall probably feel stimu
lated to preserve . Then in the rock or coral itself willbe more Crustaceans , some such as Hapalocarcinus andCryptochirus , which have been grown over by thecoral
,an d others like the barnacle
,Pollicipes, a true
borer , many worms of all sorts,Mollusca such as
Lithodomus the date stone,and a few Gastropods ,
masses of brown boring sponge,an d many other
animals of odd groups,such as Octopods or cuttle-fish
which have annexed the holes made by others . All
m ay be preserved in strong alcohol,preferably being
first killed in weak spirit . Another method of peculiarvalue
,especially when one is pressed for time
,or night
is approaching,is to place the rock masses in a tub or
basin of sea water,and to leave them for some hours
or the night . The animals soon get starved for oxygen ,
and many come out of their holes,being easily picked
offwith forceps .
Of other free - living forms there are the sea- spidersor Pycnogonids
,which Should be placed in small tubes
of strong spirit,not more than two or three together .
They crawl on the fine branches and stems of weeds ,hydroids
,and especially Polyzoa . Then there is the
great group of flatworms,or Turbellaria ,
which dwellmainly on the under surface of stones , crawling betweenthe sedentary sea- squirts or Tunicates , and takingrefuge in any hollows of the rock . Most are small, and
AN IMALS 79
can be induced into tubes held under water against thesurface o f the stone . They can then be killed with afew drops of formalin dropped into the sea water in thetube
, and at once corked up in the same fluid . Foram in ifera
,minute unicellular organisms with complicated
Shells (Figs . 1 1 to can be seen creeping up the glasssides of any tumbler or. glass into which some clean sandfrom below tide- level has been placed . We know littleof their life-histories even in temperate seas
,and tropical
forms are mainly of interest to us for comparison oftheir shells with those in various elevated rocks . We
get their shells by simply drying the sand—Te ,in the
various sand samples We have already collected formore general purposes . Of insects we m ay mentionHalobates (Fig . seen on rock- pools , though a wanderer over all tropical oceans . Its eggs and larvae areoften found on floating cuttle—bones and pumice
,fre
quently being confused with young barnacles . Needless to say any insects in salt water are of value , andshould be carefully preserved in 70 per cent . alcohol .There is a Spider also (Desis) the distribution of whichis interesting . Lastly
,we have snakes (Hydrus) ,
dangerous pit-vipers , but yet timid beasts , incapableof harm so long as the body is covered
,and the thin
parts of the hands are kept well above the surface ofthe water .
Of sedentary animals we might make a catalogue ofHydroids , soft corals (Alcyonaria) , anemones , corals ,sea- squirts (Tunicata) , sponges , and Polyzoa
,and say
that pieces of any and all placed in 70per cent . alcoholare likely to be of value to specialists
,particularly when
smaller slips for anatomical purposes are put in 90 percent . alcohol . We are , however , at the present daybeset with difficulties at every turn in respect to thedetermination of the species of these forms . They have
0 80 THE SHORE
F IG . I I .—M1LIOLINA . FIG . 1 2 .
NOD SOAR IA .
F IG . I 3 .—A STRORHIZA . FIG . I4 .
—PENEROPL IS .
TYPE S OF FORAM IN IFERA (BLAKE ) .
82 THE SHOREfor the most part floating larvae , which can be carriedby ocean currents over wide stretches of sea ,
an d
accordingly present relatively little variation of speciesover each of our two great tropical ocean s . Let thenaturalist collect a few groups only ,
but let him studythe growth of those few carefully on the spot in relationto their environment . It does not matter whether heknows the names of their groups
,families
,genera ,
an d species , or not . AS we have already said,he
cannot go wrong , for such intensive studies of tropicalbeasts have never been made . He will have thesatisfaction of knowing that he is at least adding something of high permanent value to biological science ,and he will be undertaking a study the interest in which
grows as the work continues .
B .—Coral Reefs and Islands.
In the previous section we have already sufficientlyemphasized the paramount importance of ascertainingthe nature of the geological formation of any islandwhich may be visited . Islands divide themselves intothree classes, continental, volcanic, and coralligenous,in accordance with the composition of their rocks ,though it is not always easy to separate them . A
continental island is one which ,from the nature of its
rocks,or more generally from the considerable variety
of the animals and plants which live upon it , mustbe supposed to have been at one time connected withsome continental mass of land
,upon the surface of
which , according to our present views , a large varietyof animals and plants m ay be supposed to have beenevolved . Thus , for example , all the greater islandsof the East andWest Indies must have been connectedat one time with their neighbouring continents .
ISLANDS 83
There is little room for doubting (see Fig . 2 1 ) thatMadagascar was at one time j oined to Africa ,
and NewZealand to Asia and Australia through New GuineaNew Zealand may have had also a polar connectionwith South America . The Seychelles I slands are
formed of granite , a type of rock essentially associatedwith the immense early solidification s of eruptionswhich formed great continents . They doubtless were a
part of the Indo -African Continent , which is believed
Pac I f I C
O c e a n
FIG . 2 1 .—CHART OF THE \VORLD , SHOWING THE SUPPOSED D ISTRI
B UTION OF LAND (D OTTED ) IN THE CRETACEOUS PER IOD . (AFTERNEUM AY R . )
by many to have once extended between Africa andIndia Gondwanaland ,
” as it is often termed .
The Fij i Archipelago is a more doubtful case ; it srocks are of recent volcanic types , overlaid by soapstone
,composed of submarine deposits formed largely
by Foraminifera,and by raised coral rocks . Its fauna
and flora,however
,are
,comparatively speaking
,rich
and varied , but it must always be remembered thatthe numbers of species and genera of animals and
84 THE SHOREplants on any land vary proportionately to its size ,temperature , varieties of soil , an d rainfall ; the exactinfluences of each of these cannot , of course , be exactlystated . In the case of islands formed by submarineeruptions
,their proximity to other lands
,and the
presence or absence of currents and winds,suitable
for the transport of the seeds and germs of plants andanimals , are of primary importance . Hawaii
, Samoa ,
and Tahiti were probably all formed by eruptions,and
to some degree they illustrate the influence of distanceand size already mentioned . Mauritius
,Réunion ,
andRodriguez are probably further examples but theformer m ay have been connected to the Seychelles ,and so to Africa and Rodriguez was partially formedby an upheaval of the sea- floor . The Atlantic Islandsthe Canaries , Cape Verdes , and Azores—are probablyall of similar origin , though some of them have beensupposed to represent the remains of a continentconnecting Africa to South America .
It will be now clear that the importance of the studyof islands to a large degree depends on the light whichthey throw on the existence of former continents—on
the distribution of land and sea in past geologicalperiods . An island m ay exist where we are practicallycertain that there was formerly continental land ,
butit by no means follows that it was ever part of thatcontinent
,since it m ay have been formed subsequently
to the submersion of the continent . Yet it is in islandsthat we might expect to find our best evidence of theexistence o f former connecting land masses .
The interest of our third class of islands—coral islandsis again different , and l ies in the question , how far
do they indicate the sites of former land masses whichhave disappeared by subsidence or from other causes PSome of these islands have been elevated to great
86 THE SHOREexist
,while on their western shores , as , for instance ,
to the east of Africa and Australia , they attain greatdimensions . Their Shape and appearance whereverthey exist is quite characteristic , a flat
,almost level
with the surface of the sea at low tide , on which theocean pounds down , even in the calmest weather , withgreat breakers upon at least one face . The water at lowtide flows over the flat for some distance
,only to rush
FIG . 2 2 .—CORAL OOLITE . FIG . 2 3 .
—CORAL B RECC IA .These are form ed by the grinding down Of coral bou lders , the frag
m en ts being c em en ted together by the dep osition of lim e atd ifferent grades of fin en ess . B oth found abundan tly on theshores an d in the islands of atolls B lake
back by countless fissure- l ike channels in the edge ofthe reef . This area , the reef flat, as it is termed ,
ismarked off on its inner side by a band of boulders
,
generally small masses of reef rock or coral colonies,
which have been hurled up from inside or outside ofthe
'
reef hence is derived its name of the boulder zone.
Instead of these boulders we may have a land,per
chance formed by them,perchance of elevated coral
CORAL REEFS 87
rock or of volcanic material,the Shore of which
,in
most cases,is boulder- strewn . The reef will thus form
a narrow shelf aroun d the land , being then termed a
fringing reef (Fig . Sometimes the land behindis separated from the boulder zone by a channel thismay be only a few feet in depth
,when it is termed a
boat channel, or it may be some fathoms deep ,sufficient
for a ship ’s anchorage,when it is commonly called a
lagoon . To a considerable degree the depth of thislagoon depends on the distance of the land from thesur face reef outside , but it never exceeds 50 fathoms .Inside of most reefs
,within the boulder zone
,there is
almost invariably (if no island arises within the limits
Low tlde lav
F IG . 24 .—SECTION OF FR ING ING R EEF , ROTUMA I SLAND SPAC IFIC OCEAN .
a , Land b, b, boat chann el or lagoon flat c , e , bou lder zo ne d , d , reefflat e , crest or edge of reef ; f, f , seaward slop e .
of this zone) a broad flat,with 1 or 2 feet of
'
water
at low tide , more or less covered with sand ,part bare
,
part rich in coral growth . This m ay be termed thelagoon flat, and may be the flat beneath our boatchannel
,or may be a flat before the water deepens to
form the lagoon . Such a reef , with a deep lagoonwithin it around the land , is termed a barrier reef,but there is no Sharp transition between it and thefringing reef .Lastly , the reef may exist as an isolated structure byitself , with its reef flat , boulder zone , and lagoon flat .
It m ay be—(I ) a small mass completely swept by the
breakers ; or (2) a larger reef with amere pile of bouldersin its centre ; or (3 ) with the smallest puddle of water
88 THE SHOREin a ring of boulders ; or (4) with a great shallow lagoonflat a mile or more across ; or , lastly , (5 ) with a lagoonflat and a deep lake
,like the lagoon above . In the
latter case it is termed an atoll (Fig . Then it isessentially a ring of reef , bent as you will , surrounding
Gr an d?
PP'HQ
FIG . 2 5 .—A TYP ICAL ATOLL ; PERO S B ANHOS , CHAGOS GROUP .SCALE , 4] M ILLIMETRES I M ILE . (FROM THE ADM IRALTY
CHART )
a lake , the lagoon, which may be a mere pool or a greatenclosed sea (thirty or forty miles across) , which , however , never attains a greater depth than 50 fathoms .
*
This is tru e for the lagoon s of both atoll and barrier reefs ,with on e exception—n am ely , that of Van ua B alavu (Exp loringGroup ) , Fij i . H ere a bight of deep water ,
60 to 100 fathom s .
ex
ic
l
ends in to the lagoon ,sup erfic ially rem ind ing on e of a sunk
va ey .
THE SHORE
F IG . 26 .—MAD REPORA PROL IFERA : A TRUE CORAL B LAKE
An abundan t coral of the Lagoon Flat .
MILLEPORA ALCICORNIS 91
FIG . 2 7 .—M ILLEPORA ALC ICORN IS : A R EEF B U ILD ER BELONGING
To THE HY D ROMEDUSZE , BUT NOT A TRUE CORALFound everywhere on ree fs ; notic eable for its fo rm s o f growth ,
m assive to lam ellar to fine bran ches : they are adap tation s todep ths and strengths of curren ts .
92 THE SHOREcolonies by budding , the buds not separating , so thatthe whole may be regarded as a single animal with themouth
,tentacles
,and all its other parts many times
repeated .
Underneath the animal coral is being built ; of itsrate of formation we require further definite information
,but a single anemone of 1 millimetre diameter
has been known to bud out and form 693 grammesof coral in thirty- six months . Corals grow luxuriantlyin tropical waters , but of their food and of the conditions which affect them we have not as yet adequateknowledge . They have Slitlike mouths within theircircles of tentacles
,and
,being fixed
,are of course
incapable of searching for food in any way . Whencut open food is seldom found in their digestive cavities ,but they are supposed to seize the small organismswhich float in the surface waters of the sea as thelatter flow over them . Investigations on this matterare urgently needed, for which purpose crabs or anymolluscs might be cut or pounded up into small fragments
,and the anemones fed with them . Reef
forming corals have in addition,living in their
cavities,vast numbers
‘
of minute unicellular greenplants
,or algae
,which especially congregate in their
tentacles and towards their surfaces,generally giving
the living colonies a green colour . In many species ofcoral they practical ly obliterate the digestive cavitiesof the animals
,in one form the latter being absolutely
closed off so that it has no opening or mouth to theexterior . For their life and increase these algae mustbe mainly dependent on the carbonic acid gas in solutionin the water
,and they are probably largely eaten up
by the coral anemones as they require food . On e
observer states that reef corals give off a certain amountof oxygen
,but his successful expe riments were few in
94 THE SHOREsoft tissues . For this purpose fixed colonies should beselected
,such as by growing together might form a solid
platform . Massive forms with large anemones will befound most useful for the purpose
,being easier to
observe,and giving the roughest surfaces for the
lodgment of sediment . At the same time observationson the expansion and contraction o f the tentacles ofthe coral anemones , and so of theWhole animals
,might
be added, especially in connection with the ebb andflow of the tide , with the amount of sediment insuspension in the water , and with darkness and light .Whatever be the cause
,it seems certain that the
ordinary reef corals do not grow in any luxuriance ata greater depth than 30 fathoms , though isolatedcolonies have been dredged as deep as 50 fathoms .
Down to 30 fathoms the larva of coral anemonesaffix themselves in vast numbers on any tropicalcoast or suitable bank ,
if there exist rocks or stones fortheir attachment . Each rapidly becomes a full-grownanemone
, and buds off fresh anemones , quickly forminga colony supported on a massive skeleton of carbonateof lime . As some of the anemones die or are killed ,
fresh surfaces of rock are left for the fixation of furthercoral larva , and finally a rough platform is built upto the surface of the sea ,
beyond which growth is, ofcourse
,impossible . In this way a fringing reef may be
formed round any island with a depth of 30 to 40fathoms off its outer face
,or a reef may be built up on
any Shallow bank to the surface . Corals are the mostimportant organisms in its structure , but the remainsof molluscs
, starfisheS ,soft corals (Alcyon ida ) , Polyzoa ,
and a host of other animals assist as well . Alga alsoare important , both calcareous leaved forms , such as
Halimeda (Figs . 50, 5 1 ) and the more massive skeletonsof Lithothamn ia (Fig . 75 ) as firm and strong as those
GROWTH OF REEFS 95
of the corals . Sand , partially the remains of the aboveorganisms , but largely composed of the shells of pelagicunicellular organisms (Foraminifera) , collects betweenthe corals an d helps to solidify the whole structure ,while creeping and spreading Lithothamn ia form a
surface firm enough to resist the mightiest breakers .
The relative share o f each organism varies in eachlocality
,and is always a matter of interest .
Let u s now trace further the probable fate of ourreef before proceeding to controversial theories . Itsbreadth will depend on the area of the shoal on whichit was founded , or on the area within the 30- fathomline round the land . It will be a flat on the surface
,
with the corals dead on the top or represented only bysmall colonies of poor growth . The sea will be surgingup around
,bringing abundant food to its face
,and
here corals will be found gron vigorously as deepas the eye can see
,1 5 fathoms or more . The rollers
will be constantly pounding down on its edges andbreaking off colonies , a few of which may be cast uponthe surface of the reef to form a boulder zone
,but
most of which will be washed outwards to bring freshareas within suitable depths for the reef builders . As
this process continues,the reef will be spreading farther
and farther seawards,broadening i ts surface
,and
making life less and less possible on its inner zone asthe animals become more distant from their chiefsource of food- supply
,the open waters of the ocean .
This process might contin ue indefinitely , the rate o foutward growth depending on the steepn ess of theouter slope of the ocean floor . The outgrowth mustbe assumed to result finally in the (almost universal)gradual slope for about 200yards to about 40 fathoms ,followed by the steep slope
,often with an angle of
over 40 degr ees to about 1 40 fathoms . At this depth
96 THE SHOREthe regular contour of the ocean floor is reached
,
* thoughit must be Slightly altered by the deposition of coralmud and rubble from the reef above . The cause of theexistence of the first slope to 40 fathoms is not known ,
though it has been supposed to be connected with thedepth to which the effects of wind-produced waves arefelt .
Further observations on the currents,bottom con
dition s, and fauna of the outer slope , are urgentlyneeded . The steep is clearly a talus formation
,
resulting from the outwash of loose masses of coralfrom the reef above , its angle of slope being the angleof rest of such masses in comparatively calm water .The theory of the formation of atoll and barrier reefs
propounded by Charles Darwin in his Coral Reefs ,a book of genius in its lin e as great as his Originof Species , depends on the assumption that the land,round which a fringing reef has formed
,is subsiding
at such a rate that the coral and other organisms uponthe reef can , by their growth ,
keep it at the surfaceof the sea (Fig . Such organisms will grow morevigorously at the ocean edge of the reef , where they willhave more food . Thus it will be easily understoodthat
,as subsidence proceeds
,a channel (at first a boat
channel,and then a lagoon ) might be formed between
the reef and the land . This lagoon will attain itsbreadth by the gradual submergence of more an d moreof the land
,which finally might be completely sub
merged,the formerly fringin g reef becoming successively
a barrier reef and an atoll reef,the contours of these
roughly representing the former extension of the landmass . It is a theory delightful in its simplicity , but itdepends on the assumption that the land continues tosubside slowly for periods of ti me even geologically
Com p are this W Ith the slop es off con tin ents , p . 208 .
THE SHOREindistinguishable from the shoreward part of a reef .If organ isms commence to grow on the outer edgeof such a platform ,
its surface appearance is in
FIG . 2 9 .
—SECTIONAL D IAGRAM To ILLUSTRATE FORMATION OFATOLL AND B ARR IER REEFS BY SUBSID ENCE . (ADAPTED FROMDARWIN ’S CORAL REEFS .
A , A ,Sea—level of island , with fringing reef in black ; A ’
, A’
, the
sam e after som e subsiden ce —island,with barrier reef shaded ;
A"
, A”
, the sam e after the island has been subm erged—atoll
reef dotted . The vertical scale , as in the n ext figures , i s m an ytim es the horizon tal scale .
F IG . 3o .—SECTIONS To SHOW FORMATION OF REEFS BY ABRA SION
OF LAND .
I , Ongea Levu , Fiji , an elevated coral island ; 2 , Wakaya , Fiji , avolcan ic is land ; A , supposed form er section s of land ; B , p resen t
section s of land and reef .
every respect that of a true reef . This is esp eci
ally the mode of formation where the land is composed of elevated corall ine limestone , as is frequent
CORAL REEFS 99
in island groups where fringing and barrier reefs are
abundant . Again , as a fringing reef broadens , neitherthe reef flat nor the boulder zone increase greatly
F IG . 3 1 .—SECTIONAL D IAGRAM To ILLU STRATE FORMATION OF
AN ATOLL ON A MOUND OF THE SEA-FLOOR .A , original m ound B 1-B 4 building up of sam e by rem ain s of d eep
Sea an im als , by p elagIc deposits , and , lastly, by reef organ ism s
to the sea - level C1 -C3 , o utward exten sion by accumu lation of
talu s and o ther m aterials on the s lop es and further growth of
reef organ ism s ; hollowing ou t of the surface by so lution and
rem oval of mud in susp ens ion .
FIG . 32 .—SECTIONAL D IAGRAM To ILLUSTRATE FORMATION OF ANATOLL ON THE S ITE OF AN ISLAND OF LOO SE MATER IAL WH ICH
HAS BEEN PARTLY WASHED AWAY : sUCH AN I SLAND A s IsFORMED BY A SUBMAR INE I E RUPTION .
A , Original island B , ban k after the top of the island has beenwashed away to 20 50 fathom s C , ato ll form ed by the d irectand greater upgrowth of reef organ ism s on the edge of the bank .
in breadth,the inner part (lagoon or shore flat)
broadening and taking up the extra breadth .
The shore or lagoon flat is obviously formed whereonce was boulder zone , and it should therefore bestrewn with boulders . On a broad fringing reef such
100 THE SHOREloose masses are not found on the lagoon flat , * it beinggenerally a bare or Slightly hollowed- out area
,which is
alternately covered and uncovered by the tides . Thelatter must be the ultimate agents which effect theremoval of the boulders , and this they are supposedto do by removing the coral , which is composed ofalmost pure carbonate of lime , either in solution or asfine mud in suspension in the water
,or by both means .
The solvent action of sea water on coralline material iswell determined , and organisms are likewise known tobreak up coral rock into fragments—gravel
,fine sand
,
and,lastly , mud . The removal of material in suspension
is evidently of as great importance as solution ,or even
greater,hundreds of thousands of square miles of ocean
floor near coral reefs being charted as covered withcoral mud . How the latter is produced requires furtherinvestigation . Probably there is some animal matterleft in the coral l imestone . In search for this themasses of rock are riddled in the first instance withthe fine borings of alga (Achyla) and sponges
,their
borings invisible to the naked eye . These are followedby worms
, Sipunculids , and hosts of other organisms ,which cause the rotting to pieces of large masses .
They are further broken down by the waves into graveland sand ,
as such being ingested by other worms, sea
urchins, Holothurians , Sipunculids , and Balan oglossids ,
which in their intestines further grind them up intothe finest mud ; the latter readily passes into suspension
B ou lders form ed of the skeleton s of the blue c oral ,He liopora ,
o ften p ers ist for long per iods of tim e , resistingm ost
of the ordinary agenc ies which in such p osition s cause decay .
The sam e is also true to som e degree ofMillepora , the stingingcoral , ” which is a form of pecu l iar anatom ical interest , as
having m edu sa bear ing the generative products (F igs . 27an d
102 THE SHOREto which it gives entrance .
* The latter depth is apparently fixed by the first seaward slope
,a gradual one to
40 fathoms or thereabouts , this approximately beingabout the depth to which lagoons generally attain .
Observations on these matters are urgently needed ;they should be accompanied by precise information asto the conditions ind ifferent parts of the lagoon of coralgrowth , sand deposition (exemplified by samples) , rateof currents , etc . Estimations of the amount of solidmaterial carried into and removed from the lagoon bythe tides are wanted , and may be made by suspendingplankton nets of fine mesh—we suggest two kinds ,60and 1 80meshes to the inch—in passages leading intothe lagoon for one , two , or more hours at ebb and floodtides both in calm and stormy weather
,and at different
depths . A good current meter (Ekman) might besuspended from the same anchor chain between two ofthe nets .
The above theory of the formation of lagoons bysolution an d erosion offers no explanation to accountfor the submarine foundations on which atoll reefs arebuilt up . It is conceivable that islands , which wereoriginally surrounded by fringing reefs
,m ay have been
completely removed by abrasion and solution , the reefbecoming successively of barrier and atoll type . Thismode of formation is seen in the windward group ofFij i (Fig . where the islands are mostly formed ofraised coral rock ; but atoll formation by this means isprobably not of wide occurrence . Secondly , an islandmay be cut down by the action of wind , waves , and
Som etim es rounded growths of Lithotham n ia are comm on
in su ch a p osition . Often the s ides of such chann els are r ichdredging-groun ds for seden tary organ ism s
,esp ec ially Gor
gon ian s, Polytrem a , an d Hydrocorall in es . Where the lagoonis large and there are several chann e ls , this question of depth
becom es comp licated . It shou ld be re-in vestigated in each atoll .
ATOLL FORMATION 1 6 3
ocean currents to form a submarine bank ,no fringing
reef forming while the process is taking place,owing
to sediment produced by abrasion . On such a bankan atoll would be built up owing to the more rapidgrowth of corals on its rim , where they would be betternourished . Submarine eruptions may occur anywhere ,and the contact of the molten lava with ' the waterproduces a mound of Cinders and ash ,
which may forman island or never appear above the surface of the sea(Fig . Such a mound would rapidly be cut downto the limits of wind-wave action
,perhaps even to
40 fathoms or more , on which an atoll would directlyarise
,in the way above suggested . Such a mound was
Falcon Island,Tonga
,erupted in 1 883 to a height of
about 250 feet , but now a submarine plateau coveredby a few fathoms of water .
Thirdly,mounds might be built up beneath the sea
to suitable depths for the reef builders by the remainsof various organisms . On any slight elevation on theocean floor sedentary and other animals congregate toan extraordinary degree . Chief among these are thedeep- sea corals
,enormous banks of which have been
discovered on the floor of the Atlantic by dredgingand sounding expeditions . Their remains
,assisted by
the remains of pelagic organisms , build up the surfaceof the mound to an extent out of all proportion to theupgrowth of the surrounding area of the ocean floor ,so that the mound ultimately approaches the surface
(Fig . The reef builders obtain sway,and a reef
soon reaches the surface,later to Spread out on its
own talus and to be hollowed out in its centre,forming
a typical atoll .In many coral- reef regions boats are often difficult
to procure , and the traveller is driven to study thelow- lying islands which are so characteristic of coral
104 THE SHOREreefs . A fewwells probably exist , which give adm irable sections of the land
,an d
,labour being cheap
,others
m ay be dug so that its structure is made thoroughlyclear . We ask a few questions of the traveller . Are
the islands growing or washing away,either on their
seaward or lagoon sides , or on both ? Are - theyextending farther along the line of the reef Whateveris happening to them
,are they all following some
definite law,or is each apparently adapting itself to
its own immediate environment ? On the flat reefitself large bare masses of coral rock are often seenstanding up as high as
,or even above
,the high- tide
level . Are they pinnacles,and
'
therefore part of thereef on which they are standin g ? or are they masseswhich have been hurled up on to the surface of the reefby the waves in storms In all cases they are valuablefor the study of the formation of the coral rock fromthe heterogeneous series of organisms which build a
reef . Ordinarily they are washing away,and present
j agged points of coral worn out . If they are part of thereef below this coral should be in the position of growth ,
a fact which can be easily ascertained by comparisonwith the corals growing in the vicinity . Any evidenceof stratification anywhere will be of value . Pools ofsalt or brackish water in the islands are always ofinterest in connection with the formation of the islandsthemselves . In the land fauna an d flora there isperhaps little interest
,but the visitor or trader who
calls at all islands of a group or a large series of islandswould render service by recording the flotsam andj etsam which reaches them ,
in reference to the possiblepeopling of islan ds recently formed or otherwise bare .
The residents will point out peculiar trees , and theexamination of growing- out spits
,etc .
,will reveal many
seeds .
1 66 THE SHOREFor work on land , on the shores , or in the sea , khaki
clothing (cotton) is recommended Norfolk j ackets,
with plenty of pockets ; breeches fairly tight at theknee ; puttees and boots, either ordinary navvies at6S . to I OS .
, or especially made and studded with smallscrews at about 25 3 . topee coming well down behindand strong leather belt .
The regular tropical clothes can be bought moreeconomically in the tropics , and the cost is about asfollows White duck or twill suits , j acket and trousers1 4s . ; Indian tennis shirts , 2S . ; white canvas shoes ,about 6S . best topee , 1 5s . to zos . khaki suits , Norfolk j acket and breeches , 1 5S . ; puttees , 2S . ; secondtopee , 7S . 6d . The cheapest cloth , etc .
, is not found tobe most economical . If travell ing eastwards and notdisembarking at Colombo , Singapore , or Batavia ,clothing can be obtained on the voyage , the travellerbeing advised to pay a little more and go to such goodfirms as Simon Arzt , at Port Said or Cowasjee ,
Den
shaw,and Company
,at Aden .
The traveller is strongly recommended to observethat Englishmen dress in the tropics as carefully as
they do in England,and that he will prej udice himself
in the eyes of whites,and even more in those of natives ,
by inattention to the cleanliness and neatness of hisperson and dress when not actually engaged in hiswork .
The naturalist is advised when at work in the water ,even if diving for corals
,etc . ,
to wear the above dress ,only
,perhaps
,dispensing with his coat and topee when
being constantly submerged by theWaves . Abrasions ofthe skin and the subsequent entry of poisonous substances will thereby be averted . Sun blisters of armsand back will also be avoided . One or two p airs ofstout woollen socks will assist the fitting of boots .
TROP ICAL OUTFIT 1 9 7
The salt water will do him good , and any dryness ofthe skin can be corrected by rubbing on coconut oil ,which will also be found quite efficacious in keepingmosquitoes off the face , hands , and neck . A regu larmosquito sleeping-net l is essential if there is to be anyshore living buy a piece of calico 6 feet by 30 inchesand 6 yards of best mosquito netting 72 inches widesew the netting all round the calico
,to the corners o f
which suspending cords may be attached . A waterproof sheet , such as is made by Andersons of St . Paul ’ sChurchyard , is also useful . It is perhaps unnecessaryto add that all clothes , particularly boots , should bewashed in fresh water after being wetted by sea water ,and that needles and plenty of thread will frequentlysave much expense .
Medicines, etc .—For zos . to 305 . a quite suffi cient
stock for an ordinarily healthy man can be procured ,
perhaps a small tin case from some well-known firmof makers
,10 by 6 by 6 inches . Its actual contents
will vary with the peculiarities of each individual .Heal th in the tropics is treated of in many pamphletsand books , giving the use of simple drugs and methodsof bandaging , etc . The author , who , having had considerable experience , is able to adapt common materialsfor his purposes , takes with him a double knife lancet ,two Clinical thermometers, four baridages of differentbreadths , a card of safety-pins , cotton-wool , a smallpacket of cyanide gauze
,a packet of lint
, 4 ounces ofzinc ointment made stiff
,dark glasses
,a wooden phial
of tabella of cocaine in case of eye- soreness , and2—ounce bottles of each of the following drugs : sulphate of quinine
, 5-grain tabloids ; salicylate of
quinine, 5—grain tabloids sodium salicylate (the
natural salt) , loose ; Dover’s powder
,loose ; ipecac
uanha, loose ; bismuth subnitrate , tabloids , 5 grains ;
10 THE SHOREboracic acid , loose chlorodyne in liquid cascaraextract in liquid rhubarb and calomel pills Warburg ’stincture of quinine , in liquid . Also smaller tubes o fthe following arsenic and strychnine calomel
,
flljgrain chrysophanic acid , powder clove oil ; strong
myrrh and borax ; corrosive sublimate . The novicewill require small scales .
The above is intended to be no full list,but it may
be useful as serving for a basis for discussion betweenthe intending traveller and his medical man . He m ayalso require some sedative drug
,for which ammonium
bromide is suggested this will be found of great valuein nervous sea- sickness . The chrysophanic acid
,
is
essential for ringworm . The bowels must be keptproperly open . I f residence among wild ” natives isintended , a few cheap strong purgatives and plenty ofquinine should be kept ; dentistry also is always a
great pleasure to natives,and
,if practised , will make
many friends .
Photographic Apparatus—The value of photographyon tropical ree fs and shores is well illustrated by themonographs of Professor Alexander Agassiz . Photographs often give an idea of a reef or shore , of whichno mere word descriptions are capable . They also giveincontrovertible proo fs o f many facts . The writerhimself uses a stand camera ,
brass-bound , with Russianleather bellows
,the whole of the most expensive make .
I t has been three times immersed in the sea, and isstill almost as good as ever after nearly four years ’rough service in the tropics . He uses plates , ordinaryWratten or Ilford
,which he always gets sealed up by
the makers,and which he has found good after eighteen
months of tropical heat . A watchlike exposure meteris essential
, as the photographer from temperate zonescannot judge the actinic properties o f the tropical
1 10 THE SHOREand gimp of varied Sizes , to be fitted out as requiredin different places .
The naturalist will be guided by his own inclinationsas to whether he carries with him dissecting in struments . He will certainly require two pairs of ordinarycoarse forceps
,one of which he will be well advised to
attach to his belt . A good sheath knife in his belt
(cost with sheath 28 . 6d . ) is advisable . A satchel isnecessary, and should have two pockets , one for fulland one for empty tubes ; two of the ordinary whi tesoldiers ’ knapsacks will do as well, and perhaps be moreconvenient these will cost 5 5 . or less
,but the natur
al ist will satis fy himself better In the end by makinghis own bag from a length of canvas to suit the idiosyn crasies which he is bound to develop . A couple ofcommon galvanized buckets are as good as anythingfor the larger Specimens of the catch
,while an enamelled
billy (a pot with a lid and swing handle over same) willserve for more delicate beasts ; glass tubes , of course ,also being carried . Enamelled basins serve for sortingthe catch , aided by ordinary plates , pie-dishes , and
everything of a similar nature that can be found . Twobasins and half a dozen
“
plates will be suflicient, as ageneral rule , for a good day
’s catch .
The alcohol used for preservation should be purespirit , not methylated in any way . It is bought as
96 per cent . Spirit , and is obtained best from theColonial Sugar Refining Company , Sydney , Ncosting 23 . per gallon . It is also distilled in Mauritius ,Java, and many places in the West Indies , but pricesof 3 5 . to 45 . are frequently asked
,and a stock is not
kept . It may, perhaps , as well be purchased fromsome reliable English house (23 . 6d . per gallon , To
-gallondrums, returnable) , who will see that it is shipped .
Formic aldehyde (see p . 347) will also be required it
CHEMICALS 1 1 1
is not good for animals with calcareous Skeletons orscales , turning Slightly acid , especially in the tropicsthe much more expensive German patent formalin isno better . For the minute anatomy of tropical marineanimals the best all-roun d killing agent is undoubtedlycorrosive sublimate (mercuric chloride) in saturatedsolution in sea water . Picric acid is also valuable ,but the naturalist is warned that it is dangerous tocarry
,being explosive it is forbidden on mail steamers
by the Board of Trade regulations .*
Various ana sthetizing agents are used in temperateregions, with excellent results , but most of them arequite useless in the tropics , the animal s it is desired toObtain expanded being frequently found to have rottedbefore the ana sthetic has taken effect . Pure Spirit , afew drops at a time , placed on the surface of theWaterwith a small pipette , i s the only really good agent , asit keeps the water clean , while gradually ana sthetizingthe beasts in
'
it . It is very good for B alanoglossidsand worms . General ly sp eaking , it is a ru le in thetropics to get an imal s as quickly as possible into oneof the two preserving fluids, in which they can bebrought home—Le , 70 per cent . alcohol , or 2 to 4 percent . formic aldehyde .
To advise as to the amount of j ars , bottles , andtubes to be taken to any trop iceil locality is quitebeyond the author ’ s powers without his knowing theprecise circumstances of each expedition , and is also ,perhaps, beyond his province . Very much may bedone with cheap galvanized tanks with screw lids
,of
1, 2 , or 3 gallons, the individual animals being wrappedand tied up in butter- cloth , each with its label statingwhere collected , etc . The spiri t may be carried in
The m ost recent regu lation s ordain that it shall on ly becarried in Solution ( 1 9 1 I ) .
THE SHOREthese tanks , and when a large number of localities areto be visited , it is as well to keep a tank for each .
Lastly, wewould emphasize the importance of dulylabelling
'
all tubes, bottles , and specimens , with localitywhere obtained and date . A duplicate of the labelmay be obtained with carbon paper, and is often useful .It is advisable to use numbers as well as writing , therecord of these numbers being kept in a separate notebook . If due care is taken in the first instance , thebottles
,etc .
, can be packed as filled and sent home,
without being further looked after in any way . Whenbottles go wrong , it is generally due to their being tootightly crammed with animals, insufficiently soaked inweak spirit before being placed in 70 per cent . spirit ,or to the corks or covers being carelessly replaced sothat air can get in , and consequently fluid and vapourcan escape the latter may be avoided by dipping theirheads when thoroughly covered up into melted paraflin .
A piece of string placed in the mouth of a bottle whilethe cork is being inserted allows the cork to be screwedhome
,air escaping by its sides it can subsequently be
pulled out .
1 1 4 THE PLANTSupon the bodies o f other animals or plants . They areable to manufacture their own food from the Simplegases and mineral substances in the water . Theexternal power, by means of which their foodfactory is run ,
is in the light of the sun ,which they
intercept by the help of various colouring matters .
The plants of the sea are thus able to increase andgrow independently of the other marine organisms
,
and so ultimately they must be the source of thefood- supply of all the animals which can only live bypreying upon one another or upon plants .
The colouring matter used to trap the light is onland nearly always a green one ; in coastal plants itmay be green , red , or brown in the open sea most ofthe members of the phytoplankton Show a brownpigm ent . Only a few are green .
Collection .—The phytoplankton is , of course , col
lected in the same way as the animal plankton . Forthe various types of nets
,etc .
,reference must be made
to the section dealing with the Floating Animals . Owingto the small size of most of the vegetable organisms ,the finest Silk gauz e , of 180meshes to the linear inch ,
Should be used . Even then the meshes of such gauzeare far larger than many forms of the phytoplanktone .g.
,the Coccospheres and Rhad Spheres , and the
smaller Diatoms—So that quite 50 per cent . of thepossible catch m ay escape . The capture of all , ornearly all , the phytoplankton in a sample of watercan only be achieved by slow and elaborate methods
(filtering through special filter paper or through a
porous filter of the Chamberland type) , which arenot suitable for use on board ship or for any considerable bulk of water . It is to be noted that netswhich have been in use a few times become less permeable ; this is due to the pores becoming reduced
FLOATING PLANTS 1 1 5
in size by fragments of D iatoms and other organisms ,which become entangled in the meshes the efficiencyof the net as a filter is thus reduced , and the totalcatch becomes smaller in quantity but containsorganisms of smal ler size than were captured when thenet was new . The decrease in permeability in suchnets is progressive with use , so that finally they willhold water like a bucket . Such nets should be discarded
, or washed by rubbing gently in soap andwater
,though after such treatment they are liable
to rupture in use . For the care of silk nets , seep . 1 89 .
Owing to the small size of the plants , the phytoplankton suffers less damage than the other organismswhen collected from the water pumped through theship ’s hose . This method , however , is not to berecommended if any other is available , as the or
ganism s always suffer some damage from the roughtreatment to which they are subj ected . The fact thata certain amount of grease from the ship ’s pumpsalways finds its way into the collecting net , and thatthe water necessarily comes from one particular depth ,
—that of the intake—are also further obj ections tothe method .
For the capture and detention of the minutestplants numerous Special methods have been devised
,
but so far as we know not even their authors are as
yet wholly satisfied with them . For collection at thesurface
,nothing is better than to dip up a series of
buckets full of water , and to empty them . into a filterof closely woven undyed silk fabric (not a boltingcloth) . Below the surface
,but still at small depths
,
Lohmann has used a hose lowered to a known depth,
and by a small hand-worked centrifugal pump delivering into a filter , has obtained very good r esults .
1 16 THE PLANTSFrom greater depths K ofoid
’
s water-bottle brings up20 litres of water , a quantity suffi cient to yield a fairsample of the minutest forms . The instrument is,however
,rather expensive (about
Preservation of Material .—If only the larger formsare required , the catch can be treated in the same wayas the other plankton (p . A solution of formalin
(1 part in 6 to 10 of water) is perhaps the best generalpreservative , but will dissolve the lime in Coccospheresand Rhabdospheres .
Nature of Phytoplankton .—The representatives of
the marine phytoplankton fall into six main divisionsDiatoms , Peridiniales , Pyrocystales, Coccospha rales .
Green Alga , Blue-Green Alga (Cyanophycea ) , andBacteria . By far the larger number of forms arefound in the two first groups .The Bacteria are a very special group of plants
,
mostly colourless , which , owing to their excessivelyminute size
,are not secured by the ordinary methods
of capture, and so will not be dealt with here .
Diatoms.
—Organisms of this class are found in all
marine water , and sometimes in such enormous numbers (for examme , in Scotch lochs at certain seasons)that a net
,which is towed only for a short time
,is
found after draining to be partly filled with a pastybrown mass .The distinguishing feature of all the diatoms is thepossession of a translucent coat or Shell , consistingmainly o f silica . The shell is made of two halves
,
which,in the case of circular forms , fit into one an other
like the top and bottom of a pill-box , the edge of oneportion overlapping that of the other . In some formsthe double nature of the shell is clearly Visible , whilein others it is hardly distinguishable . Inside thetran sparent shell is the living body of the plant , of
1 1 8 THE PLANTS
DIATOMS 1 1 9
1 20 THE PLANTSPeridiniales .
—This group Includes a very large proportion of the phytoplankton . The D iatoms seem tobathe chief constituent of the phytoplankton in colderwaters, while the Peridiniales seem the more conspicuous group in warmer seas .
The members of this group are easily distinguishedfrom the D iatoms . Their wall is generally less transparent , so that the contents are not so clearly seen ;and i t is marked out , not into two portions merely ,
but into a number of angular plates fitting closelytogether . The plates may be smooth
,but are usually
marked with a number of pits . The walls consist notof silica
,but of cellulose
,the substance which is the
main constituent of paper . Running round the bodyof the plant is foun d a well-marked groove , the horizon tal furrow , which IS connected at one point with a
pore in the shell . From this aperture there grows outfrom the living substance of the body a long , whiplikeswimming organ , the flagellum ,
which proj ects freelyinto the water . Arising from the same aperture isanother flagellum
,which lies in the horizontal groove
these flagella can only be seen with considerable difficulty . The position of the horizontal groove variesmuch in different forms . In some cases , as in Ceratium
(Fig . it divides the body into two equal halves .In other cases the furrow is found quite at one end ofthe body i t may also occupy all intermediatepositions . Running up from the pore there is usuallya Short longitudinal furrow ,
which is , however , farless conspicuous than the horizontal one .
The form of the body is wonderfully diverse in thisgroup , Nature seeming to have given herself a freehand in the development of the most bizarre shapes .
Some possess long , thin spines in others the body isenormously elongated , or rounded and su ollen others
1 22 THE PLANTS
FIG . 38 .—TYPES OF CERATIUM .
FIG . 39 .—ORN ITHOCERCUS . (B OTH FIGURES FROM SCHUTT 'S
PFLANZENLEBEN D ER HOCHSEE , ” BY PERM I SSION OF MESSRS .L IPS IUS AND T I SCHER .)
FLOATING PLANTS 123
FIG . 40.—HALOSPH}ERA . (FROM MURRAY ’S INTRODUCTION To
THE STUDY OF SEAWEED S , BY PERM ISSION OF MESSRS .MACM ILLAN . )
In the sphere on the left the protop lasm has gathered round the
nuc lei lin ing the wal l ; that on the r ight has shed the outer
m embran e , and the daughter cells have separated from thewall below are four stages in the developm en t of the zoosp ores .
F IG . 4 1 . FIG . 42 .PERID INIUM . (AFTER CLEVE . ) TR ICHOD ESM IUM B LAKE
1 24 THE PLANTSwhich encloses a living body containing a number ofdisc- like green structures (Fig .
B lue Green Algae or Cyanophycea .—A small
number of the members of this group are pelagic ,though most live in fresh water . They sometimesoccur in enormous numbers in tropical seas , forminglarge floating masses . They are usually threadlike
,
and arranged in groups or bundles . One form , Trichodesm ium erythra um (Fig . is of a reddish colour ,and probably accounts for the special name of theRed Sea, for periodically it occurs in enormousquantiti es in those waters .
CoccolithOphorida .—These forms , on the border
line between animals and plants,are very minute ,
and are only met with occasionally in plankton caughtin the ordinary way, since their size allows themto pass easily through the meshes of the finestsilk net .
There are two chief forms,known in oceanic
waters—Coccolithophora (Coccospha ra) and RhabdoSpha ra . When fresh they contain one or two brownor greenish plates ; frequently , however, they appearas mere skeletons , consisting of a number of closelyarranged plates forming a Spherical body . The platesare perforated in the centre in Coccolithophora , andhave each a central proj ection in Rhabdospha ra
(Figs . 43 ,The plates consist of calcium carbonate
(chalk) , so that the organisms are lost if the materialis preserved in any acid fluid .
As only the waters of the Mediterranean have beeninvestigated for these forms by methods other thanordinary tow nets , it would be of great interest todiscover their distribution in oceanic waters generally .
For the minute forms,with which a filter is used ,
set the filter so that it never runs quite dry , but that
THE PLANTS
B .—Fixed Plants.
BY MRS . DR . A . WEBER—VAN BOSSE .
After a storm heaps of plants are cast ashore by thesea
,especially if the coast is rocky . On closer exam
ination , these entangled masses are found to consistof green , brown , purple , or bright red plants .
What are these Where do they liveThese bright- coloured plants are alga ,
or flowerlessplants
,distinguishable by their col our and various
shapes from marine flowering plants the latter have,
as a rule , narrow, long , linear leaves of a dark greencolour
,as, for instance , the common sea grass , Zostera
marina,so well known
'
on English coasts .
This section treats only of attached or fixed marinealga ,
not of the (mostly microscopical) drifting algabelonging to the plankton . A few words will be saidof alga growing in brackish water , its interesting florashowing the influence of the changing medium ; forsome marine alga migrate through brackish water intofresh water , which has , besides , a rich flora of its own .
Alga can assume the most different Shapes ; theirfronds may be either simple or branched filaments
(Cha tom orpha, Cladophora , Polysiphonia) , or ex
panded membranes of variOuS colours , composed ofone or more layers of cells (Monostrom a, Ulva , Por
phyra) they may have the form of a smaller or largerbush with stem and branches (Splachn idium , Des
m arestia, Delesseria) or look like a delicate bit of lace
(Vanvoorstia, Claudea) ; or be composed of a long ,
flexible stalk,bearing long linear blades at its swollen
top (Ecklon ia buccinalis) . Again , others form crusts ,adhering closely to the substratum (Ralfsia,
Hilden
F IXED PLANTS 1 27
brandtia) , or have fronds entirely solidified with carbonate of lime (Lithothamnium , Corallina) .The diversity of their thallus (as their fronds are
usually called) is enormous ; some are so small thatthey nearly escape our notice , and others so large thatstem and leaves have a length of hundreds of feet .But however great their outward diversity may be ,their inner structure is comparatively simple
,and built
up of either, thin or thick-walled cells . Nowhere do
we find a differentiation of these cells into vascularbundles , as in flowering plants . Neither have algaany true roots that can be compared to the roots offlowering plants ; their holdfasts are in many cases afew rootlets or a whorl of so- called hapteres ; otheralga fix themselves with a smaller or larger disc onthe substratum , and alga growing in sandy bottomhave long
,hairlike
,much-branched rootlets which
fasten themselves to the grains of sand, and enclose somany of them that
,when the plant is withdrawn from
the sand ,its rootlets present the appearance of a large
lump .
Alga have various colours,and in accordance with
these they are divided into
Blue alga—Myxophycea or Cyan Ophycea .
Green alga—Chlorophycea .
Brown alga—Pha ophycea .
4 . Red alga—RhodOphycea or Floridea .
(JO
N
H
We must bear In mind,however , that , though this
division is right in the main,there are many alga that
do not Show the colour of the group to which theybelong . Blue alga living in deep water may becomered ; red alga may turn purple , brown—red , green ,
oreven yellow, on being more or less exposed to the glareof the sun ; but with a little practice the group to
128 THE PLANTSwhich a certain alga bel ongs is easily recogn ised ; fordifferences of structure and fructification correspondwith the differences of colour .
Alga are found on all coasts in both hemi spheres ifthe outward conditions are favourable for their growth .
We find them in the Arctic as well as in the tropics,
forming a more or less well-defined belt along the coast .
Some alga grow so high up that only the spray of the seaas it is dashed upon the beach or against
,the rock can
reach them ; others live in deeper water , from whichonly a dredge can bring them up . This belt of algais divided into two regions : the littoral region
,com
prising that tract of the coast which lies dry at everyebb tide ; and the sublittoral region ,
comprising allvegetation below low—water mark . The alga of thelittoral region are adapted to a peri od of exposure at
every ebb,the alga of the sublittoral region to a con
tinually submerged existence . Both the littoral andthe sublittoral regions are again divided into an upperand a lower zone , according to the different alga foundin each for, though many alga have a wide distribution
,yet almost every Species has its own privileged
local ity in a vertical , as well as in a horizontal , direction .
Its internal organization and the external naturalagencies determine the place it will occupy . These external agencies are light , the nature of the bottom , thesalinity of the water , the strength of the currents , etc .
,
and a few remarks m ay here'
be given about them .
To understand their influence well, one has .to studydifferent local ities, for agencies exercising a certaininfluence on the coast of Greenland will have an
entirely different effect in the tropics , according totheir different combination .
Light is the chief factor every plant wants light toreduce the carbonic acid needed for its existence .
1 36 THE PLANTSThe Bottom is another factor of great influence . A
rocky and protected shore is a favourite haunt ofalga ,
though many species prefer the high surf of theexposed Shore . A rocky coast with many tide-poolsfilled with fresh sea water at every flood
,and lying
exposed at ebb tide , is a wonderful place for alga .
Collectors should bear this in mind when studying sea
charts in search for a fit place where they may expectalga .
A sandy bottom is poor in alga , on account of theshifting of the sand by the movement of the water
,
and only Species with long hair- like rootlets can contrive to live in it . For the same reason
, alga avoidplaces covered with fine mud . If
,however
, a bit ofstone or wood rises out of the mud
,i t will soon be
covered by alga .
Salinity.—Sea water contains
,on the average , in the
open sea from 3-
5 to 4 per cent . of salts but on ap
proaching the coast this percentage decreases indifferent degrees , according to the quantity of freshwater brought , by land drainage , into the sea . Marinealga flourish luxuriantly in this medium, but if thepercentage of salt fallS * considerably—for instance ,when big streams pour their fresh water into inlandseas (Black Sea, Bal tic Sea, White Sea) , and the waterbecomes brackish—true marine alga grow scarce .
The transition from a rich algal vegetation to a poor oneis
,however , gradual , and such inland seas or big estu
aries are interesting spots for investigation» Marinealga have an optimum ,
maximum ,and minimum limit,
with regard to sal inity as well as with regard to light ,and those limits lie for some species far asunder .
TheMovementof the water influences also the growthof alga . Some like places where the tidal waves rushalong the coast ; others prefer exposure to the high
TEMPERATURE 1 3 1
surf of the sea ; and , again , others thrive well only inquiet pools . Alga are admirably adapted to profit by
,
or to withstand , the strong force of the waves . Somesurf- loving alga have long flexible stalks that followthe movement of the water, while the blades at theirtop swing to and fro in the waves other alga in thesame locality can withstand the action of the waves
,
because their tissues are encrusted with carbonate oflime .
Temperature.—Some alga can endure great differ
ences
i
of temperature without damage . Kjellman oh
served in Nameless Bay, Nova Zembla,Enteromorpha
minima, a green alga, in fresh water of 0°C. , and in
sea water of 4° to 5
°C. In the tropics the alga are
exposed to the glare of the sun during ebb tide, and
in the Arctic regions Kj ellman found Laminariathriving well in a temperature of 2
°C. , and on being
exposed at ebb- tide , they withstood even a temperature of —20° C.
A lga want , however , as a rule , a more congenialtemperature , and if the coast of Norway has such a~
decidedly different vegetation from the coast of ad
j acent Polar lands,this is mainly due to the North
Atlantic Drift,whose influence is felt even on the west
coast of Nova Zembla . Still more striking , perhaps , isthe difference on the west and east coast of SouthAfrica . On the latter
,bathed by the Mozam bique cur
rent coming from the tropics,tropical and subtropical
alga flourish while on the west coast,with its Benguela
current partly coming from the Antarctic , we find a
totally different vegetation . Many more examples mightbe cited , all Showing clearly the great influence whichthe temperature of the sea has on vegetation . Pro
fessor Farlow describes how Cape Cod, in N orthAmerica, is a boundary between two vegetations . To
1 32 THE PLANTSthe north o f Cape Cod , under the influence of theLabrador current , Arctic and Northern European formsoccur to the south , with its Gulf Stream ,
species characteristic of warmer seas . Professor Setchell was ableto Show that a change in the kelp flora ofWestern NorthAmerica takes place with the increase of every 5
°C.
of surface temperature .
We touch here upon the question of the geographicaldistribution of alga . This is a question wanting carefulinvestigation
,for so many agencies exercise an influence
on the occurrence of alga in a given locality . Theresearches of Berthold in the Gulf of Naples
,of Kj ell ~
man in the Arctic Sea,of Kolderup Rosenvinge on
the coast of Greenland,of BOrgesen at the Faeroe
Islands , of Svidelius, and many others,have opened a
rich field of study with regard to the conditions ofalgal life and the physiognomy which alga give to thecoast . When searching for alga
,we observe that
large stretches of the coast are characterized by oneor two—sometimes more—alga living , in large numbers
,under the same outward conditions . Other alga
m ay be mixed with them ,but they are always in
smal ler numbers,or less conspicuous they do not put
a stamp on the vegetation , as the others do . Thus ,for instance
,Ecklon ia buccinalis is a most character
istic alga of the Cape , covering large stretches of thecoast in the sublittoral region . Little red alga liveparasitically on its stem
,but they are entirely hidden
under the mass of brown blades floating on .-the sea .
We m ay call this an Ecklonia association ,and when
several associations live under the same outward conditions we speak of a “ formation .
”
BOrgesen distin
guishes , for instance , a formati on of enc rusting alga onthe coast of the Faeroe Islands
,and all encrusting alga
belonging to it live under the same external conditions .
1 34 THE PLANTSfamilies are equally interesting from similar or differentpoints of View . Therefore collectors of alga who arenot botanists may feel sure that they can render goodservice to science if they will only collect carefully, asonly well-prepared and duly labelled collections are ofvalue .
The Myx0phycea ,or blue-green alga
,are small
,and
the least organized of the algal tribe they are eitheruni or multi- cellular . The latter form long filamentsenclosed in a common cell- sheath
,and dividing
,for
the sake of reproduction,into several portions called
hormogonia , which move out of the sheath . Theyoung hormogonia secrete a new cell- sheath
, and
develop by division of their cells into a new filament .
Myxophycea ,after having been collected
,Should ,
as
soon as possible,be spread out on the paper on which
they are to dry,and not left to stand overnight . I f
this is neglected,the horm ogonia will
,in all probability ,
have moved out from the sheaths,and the specimen
will be worthless .
Myx0phycea live , as a rule , in the upper littoralzone
,attached to stones
,pebbles , or other alga .
Lyngbya m ajuscula—the mermaid’ s hair—is some
times found floating on the sea . Some species of Calothrix (Fig . 47) form patches on the rocks
: species ofRivularia have a hemispherical thal lus , eIther solid ,
from as big as a pin ’s head to 5 inch in diameter , orhollow and forming soft expansions . SometimesScytonema and Lyngbya will cover the rocks with aslippery coating
,disagreeable
,and even dangerous to
the collector when the waves are strong . Myx0phycea
are found in all temperate and tropical seas ; theirgenera and species have
,as a rule , a very wide distri
bution . In the Arctic and Antarctic they seem to berare .
GREEN ALOXE 1 3 5
Perforating Alga—Several Myx0phycea and a few
Chlorophycea live in the Shells of molluscs , in theskeleton of corals , or in calcareous alga ,
where theybring about bluish , green , or violet spots . Theseperforating alga , as they are called , on account oftheir power to bore into calcareous tissues
, are knownfrom the
,
temperate and tropical seas . By their incessant labour they destroy many shells
,corals , and
calcareous alga ,setting free carbonate of lime .
The ChlorOphycea , or green alga ,abound in the
littoral , and are also found in the sublittoral region .
Their usual way of reproduction is by spores,which
move by the aid of cilia . Some of these spores con jugate , others germinate without conjugation . Of Caulerpa no reproductive organs are known . Many formations of green alga are known from the temperate andtropical seas . The filamentous Urospora, Cha tom orpha (Fig . Cladophora (Fig . the membranelike Mon ostrom a and Ulva (Fig . the tubelike Enteromorpha
,prevail in the temperate seas ,
while the large group of the Siphonea occurs chieflyin the tropics or in warmer temperate seas . TheSiphon ea attain a very high outer differentiation ,
buteach member of this group
,however complicated the
structure of its frond may -be,consists of only one
multinucleated cell therefore theyare called Siphoneafrom their tubular nature . Many Siphonea
—Halimeda (Figs . 50, Neom eris
,Acetabularia (Fig .
Udothea (Fig . Bornetella'
(Fig . Penicillus , etc .
—are encrusted with carbonate of lime,and to this
encrustation Halimeda owes its importance as a reefforming organism . The Caulerpa (Figs . 54 , 56) coverthe coral reefs with numerous species of multifariousaspect
,or live in a depth of several fathoms . Outside
the tropics only a few representatives of this family
SE PLANTTH1 36
1 38 THE PLANTSare known ; Caulerpa prolifera occurs plentifully inthe Mediterranean three species on the coast of NewZealand ; and five or six species along the coast
.
ofJ apan
,in the warm waters of the Kuro Shiwo
,the
Gulf Stream of the Pacific .
F IG . 5 I .
—HAL IMEDA B LAKE
To the Pha ophycea belong the Pha osPora ,the
Dictyotacea , and the Fucacea . The Pha ospora haveconjugating and non—conjugating motile spores
,all
moving about by the aid of two cilia . To this groupbelong the greater number of brown alga : the slenderfilamentous Ectocarpus family,
‘of whi ch many members
BROWN ALGZE 1 39
lead a parasitic life on other alga ; and the big Laminaria ,
the crust- forming Ralfsia so easily overlookedAsp erococcus , with its saclike frond ; and Cutleria ,with its two alternating generations , formerly describedas distinct genera under the names of Aglaozonia andCutleria—they all , and as many more , belong to thePha ospora .
F IG . 5 2 .—UD OTHEA ( B LAKE
A few details may be given of the family of the Laminariacea , or Kelps , this family being chosen because itslarge members play such an importan t part in thephysiognomy of several coasts .
When young they consist of a hold- fast , a stipe , anda linear or expanded blade , which undergoes manychanges in the different genera . They live in the
146 THE PLANTS
FIG . 5 3 .—(a ) CYMOPOL IA AND (b) ACETABULAR IA .
F IG . 5 5 .
- B ORNETELLA .
F IG . 54 .—CAULERPA F IG . 56 .
—CAULERPAPROLIFERA . RACEMOSA .
'
1 42 THE PLANTSlittoral and subhttoral zone , though it is reported thatMacrocystis pyrifera (Fig . with a frond attaining alength of 200 metres , goes down to a great depth onthe coast of Fuegia . They all love exposed placesand Darwin wrote in his Narrative of the BeagleI know few things more surprising than to see theKelp , or Macrocystis pyrifera, growing and flourishingamongst those great breakers o f the western ocean ,
which no mass of rock,let it be ever so hard , can long
resist .
Laminariacea avoid the tropics , but occur on almostall coasts in the temperate and Arctic seas . The latterare rich in representatives of Laminaria , Alaria ,Agarum ; only three Laminaria are known from thesouth-west coast of Africa .
Sacc orhiza bulbosa (Fig . common on the coast ofEngland and Norway
,is the largest European alga ,
with a height of 2 to 4 60metres , and a blade of 2 to
4 metres in length .
Lesson ia (Fig . 60) and Ecklon ia (Fig . 58) are principally inhabitants of the southern hemisphere , onlythree Ecklon ia being known from Japan . Lesson ia
fuscescens assumes,on the south-west coast of America ,
the habitus of a tree with a height of 3 to 4 metres , anda trunk as large as a man ’s thigh . From California areknown Dictyon euron ,
Postelsia,Egregia (Fig .
Eisenia,and the gigantic Nereocystis (Fig .
It is interesting to know that , however.different the
adult stages of these various genera may_be , they are
all alike in their youngest stages . This points to a
common origin,and collectors gathering Kelps should
also look for young specimens, as there still remains
much to be explained with regard to the developmentof these plants .
The Dictyotacea have light or dark brown ribbon
BROWN ALGZE 1 43
like or fan- Shaped fronds , these latter often splittingup into narrow, long pieces . Their reproductive organsare motionless eggs
,and mobile antherozoids contained
in antheridia,which form small groups
,called sori
,
visible to the naked eye , and scattered over the surfaceof the frond . Padina pavonia has a fan- Shaped frond ,
encrusted with carbonate of lime ; i t occurs on theEnglish coast with D ictyota dichotoma (Fig .
Taon ia and Halyseris but Dictyotacea otherwiseprefer warmer seas
,and flourish especially well in the
tropics . Lobospira is exclusively an Australian genus .
Fucacea .—The large family of the Fucacea is
characterized by their non-motile eggs and mobile antherozoids being contained in Special con cep tacula,
immersed either in the frond (Fucus , Fig . 65 ) or inspecial fruit-bearing organs (Sargassum , Fig . Theform of their fronds is widely different many of themhave air bladders in the continuation of the frond (Fucusvesiculosus) or special air vesicles , allowing the plant tofloat on the sea
,when it has been torn away i
from itssupport (Sargassum) . In the Arctic and northern temperate regions Fucus
,Pelvetia
,Ascophyllum ,
Himanthalia (Fig . Halidrys cover the coast with a densevegetation . In the southern region the Laminaria- likeDurvillea flourishes (Fig . Austral ia and NewZealand are very rich in Fucacea we must alsomention the necklace- like Horm osira,
with its parasiteNotheia (Fig . Scytothalia also occurs in theAntarctic . Turbinaria is strictly tropical Cystoseira,
Cystophyllum , and Sargassum (Fig . 64) belong to thetropical and warm temperate seas . Of the latter genuswe must say a few words more
,as it has a right to
claim the special attention of collectors .
In each complete Sargassum we can distinguish twoparts—a short principal axis
,with a tuft of rather
1 46 THE PLANTSbroad basal leaves , and long branching shoots of a secondary order
,with ,
as a rule , leaves of different size , airvesicles
,and special fruiting branches . When basal
and upper leaves differ from each other the transitionis gradual . The fruiting branches bear conceptacula
which are highly differentiated in the different species .
In some species the branches with male con ceptacula
seem to be cylindrical , and those with female con ceptacula dentate , but this question must still be carefullyinvestigated . I t is important
,because J . G . Agardh
divided the Sargassa into various groups , according tothe form o f the con ceptacula-bearing branches .
The genus Sargassum has approximately 1 50 species ,and is distributed over the warmer temperate andtropical seas it is especially frequent on the coast ofAustralia . One species has for four centuries attractedthe attention of men of science—Sargassum bacciferum ,
the alga of the famous Sargasso Sea . Discovered byColumbus , described by Humboldt , the origin of theseenormous quantities of drifting seaweed is
,after four
centuries,still practically unknown . There are two
Opinions about the origin of Sargassum bacciferum .
Humboldt,Forbes, Piccone , A . Agassiz
,allow the possi
bilify of the present Sargassum bacciferum being thefloating form of one or more Sargassa that lived at
tached in a former period of the earth . If this weretrue
, S . bacciferum should have propagated itselfvegetatively for long ages , because it has been collected almost always in a barren state . Kriimm el isof another Opinion . In his beautiful work , Die
Reisebeschreibung der Plankton Expedition , hegives a very interesting chart of the distribution ofS . bacciferum in the Atlantic , thereby dispelling theerror of Humboldt , who believed in the existence oftwo fixed banks of Sargassum . Kriimm el assures us
SARGASSO WEED 147
further,on the authority of Kuntze , that S . bacci
ferum and S . vulgare are identical , and he believesthat S . bacciferum is the floating form of S . vulgare
,
which occurs plentifully on the coast of the Bermudas .
But against this opinion Sauvageau has protestedmost energetically ; he maintains that S . bacciferum
and S . vulgare are not identical . By his kindness,for
which I hereby wish to express my Sincere thanks,I
am allowed to make use of letters written to him bythe American algologists, Farlow and Collins
,who
have studied the flora of the American seas , and agreethat S . bacciferum and S . vulgare are different plants .Mr . Collins , in Speaking of S . vulgare , says : Theplant in question grows attached in shallow water ;I do not think it occurs floating
,except as any other
alga that is washed ashore when torn from its fastenings
,but not continuing to live in a floating state .
”
According to Professor Farlow, it might be possiblethat S . bacciferum is a floating form of S . lendigerum ,
common in the Bermudas, but this is only a supposition and Collins , again , says , speaking of S . lendigerum ,
that its shoots soon perish after having been detached .
Farlow, Collins, and Howe agree that S . bacciferum
does not occur on the coast of America growingattached .
I t is clear that intelligent collectors could do muchto forward our knowledge of the Sargassa . Theyshould try
,above all, to brInghome entire plants, with
rootlets and basal leaves as well as with the longsecondary shoots
,and not forget that fruit-bearing
branches are of great interest .
Rhodophycea .—The greater part of marine alga are
Rhod0phycea they are usually small in size,with the
exceptiong.of some species of Halym enia,Gigartina
,
Irida a, etc . They are , as a rule , soft and slippery to
1 48 THE PLANTS
FIG . 64 .—SARGASSUM B LAKE
FIG . 65 .—SECTION THROUGH FROND OF FUCUS .
B ORNET A ND THURET . ) (AFTER
'
1 56 THE PLANTSthe touch , and of a bright red colour , except in placesexposed to the glare of the sun .
The beauty of red alga is something exquisite, and
every collector will consider his trouble well rewardedif he has been fortunate enough to collect some of theselovely alga ; for a thing Of beauty is a j oy forever .
The organs of fructification of this great group are
essentially alike , and consist of asexual cruciate ortripartite motionless spores , antherozoids , and a carpogonium with a basal part containing the egg cell
,and
a hairlike top , called the tri chogyne . The smallerantherozoids adhere to the trichogyne
,piercing its cell
wall ; and their contents , entering the trichogyne , fertilize the egg cell . After this fertilization
,a compli
cated process takes place,the result of which is the
cystocarpic fruit , consisting of a globular mass ofspores
,either borne free (Nemalion) , immersed in the
tissue of the frond (Halym en ia) , or contained withinspecial conceptacles . These latter are the typicalcystocarpic fruits proper to the group of the Rhodom elacea . Polysiphonia urceolata (Fig . commonon the English coast , 15 a good example to Show thecystocarpic fruit .
The Rhod0phycea ,or Floridea ,
are found in all seas ,but they prefer the temperate and tropical regions .
Many of their genera have a limited ,others a wide ,
distribution,but it does not follow that the species of
these latter have also a wide distribution . It m ay beso
,but more often they are limited to smaller localities .
An important group amongst the red alga is that ofthe Corallinacea
,so called on account of the carbonate
of lime which they secrete and deposit in their cellmembranes
,with the exception of the cells of the
reproductive organs and those in the j oints of the
CORALLINACEAE 1 5 1
Corallinea . By this process they grow as hard asstone
,and have for this very reason contributed
largely to the formation of the Earth ’s crust . They areknown from very early periods in the Earth’ s history
,
for Lithothamnium jurassicum is al ready reported fromJurassic strata ; in Cretaceous deposits they appearplentifully
,and in Tertiary times they were so numerous
that entire mountains were built up by them . Thewell -known Latom ien , near Girgenti , in Sicily, arequarries in rocks consisting of Lithotham nia . In ourpresent day they continue their work
,and occur in
enormous quantities,forming banks from the Poles to
the tropics,where they contribute largely to the build
ing up of coral reefs . The late Mr . Foslie , the wellknown authority on Lithothamn ionea
,kindly told me ,
in a letter which he allowed me to quote , that thenumber of known species was 276. Of these , ap
proximately 1 2 are strictly Arctic or sub-Arctic ;82 are limited to the tropics ; and 1 82 occur in thetemperate zones . For the Lithothamnionea the ruleholds good as for other alga , from warm to borealor Arctic seas the number of species decreases
,but the
number of individuals increases .
The Corallin acea are divided in many genera ; bestknown are the slender and bushhke Corallina, Amphiroa, and Arthrocardia,
and the encrusting or freebranching Melobesia
,Lithophyllum (Fig . and
Lithothamnium (Fig . The encrusting forms oftenact like mortar to cement loose material together ;the free branching forms develop into nodules evenbigger than a man ’ s fist
,and
,cemented together , they
can form masses of more than a metre in diameter .
All Corallin acea are fond of strong currents Corallinaand allied genera love places exposed to the surf of thesea ; Lithophyllum and Lithothamnium prefer the
-1 52 THE PLANTSsublittoral zone , and go down to depths even of 30 to
40 fathoms . The author has seen a bank of Lithothamnium dry at spring- tide
,near the island of Timor
,
but this is an exceptional case . . It is a curious factthat
,however large a Lithothamnium bank m ay be ,
it consists chiefly of only one species . Such banksfigure frequently on sea charts as corals .
The red alga are so numerous that it is difficult tochoose which deserve special mention . I will onlymention Constan tinea rosa marina of Kam schatka (thename implies its likeness to a flower) , Rhodymenia
(Fig . Ptilota , common in northern seas , Ceramium ,
Polysiphonia (Fig . Delesseria, Laurencia , plentiful
in temperate , but also found in tropical seas whereClaudea (Fig . 72 ) and Marten sia occur by preference .
These_exam p les could be multiplied endlessly ; per
haps I have mentioned already too many . The kindreader m ay be reminded of Harvey ’s Quaker , whosaid : Brother
,if thou knewest what I keep in
,thou
wouldst not grumble at what I let out .
In 1 899 there appeared from the hand of ProfessorW. A . Setchell a paper containing directions for coll ecting an d preserving marine alga Erythea , vol . vii . ,No . Whatever the learned Professor advises thecollector to do
,as to the best methods of collecting and
preserving alga,is the best that can be done . I can
only add a few details,and it is therefore with the kind
perm issIon of Professor Setchell that I transcribe heresome passages out of his paper . For full informationon the subj ect I refer the reader to that paper .
Collecting and Preserving Methods—Wherever acollector goes to seek for alga , he must first find outthe time of the tides from the local authorities . Thecollecting-ground should be reached from one to threehours before the occurrence of extreme low water , in
1 54 THE PLANTS
FIG . 7o .
—POLYSIPHONIA .
1 56 THE PLANTSmaterial . A good canvas or rubber bag,
with a flapfor closing the mouth , and a broad strap for theshoulder ; a basket a canvas pail ; or a large net withstraps , are all very useful implements , out of which onem ay be chosen according to the collector
’s tastes . I tis also very desirable to have some bottles with preserving fluids . To carry these we used a zinc box
(Fig . 3 5 centimetres long . 25 centimetres high ,and 1 1 centimetres broad ; it was a little concave onthe Side turned towards the body of the bearer . Insideit contained , at some distance from the bottom
,a
stand for loose bottles of various Sizes .
Specimens for drying may be wrapped at once innewspaper , a large quantity of which Should form partof a collector ’ s outfit .
A knife,well anointed with vaseline to prevent
rusting,and a fairly powerful pocket lens, are abso
lutely essential . A Spoon or a pair of small forcepsare of service in gathering from rocks small gregariousalga
,and a smal l geological hammer and chisel are
necessary if occasion arises to collect encrusting speciesgrowing on rocks . A pair of fisherm an
’
s boots withextensible legs reaching “
to the hips are necessary forwading in temperate seas ; ladies will do well to dressin a rather heavy skirt of pure wool
,and high boots ; in
the tropics a bathing- costume of thin woollen materialwill be the thing for ladies , but care should be takento protect the feet against the Spines of sea-urchinsor the rough surface of coral reefs . In some localities itwill be safer for the collector to go out with a roperound the waist
,held tight by friends in a safe position ,
on account of treacherous holes in the rocks and reefsin others the waves m ay ,
at the turn of the tide , runin S0 suddenly and violently that danger of gettingdrowned is imminent if proper care is not taken . Col
1 58 THE PLANTSor mounted and pressed , or salted , as desired . Largealga
,such as Kelps or species of Fucus
, can be verywell dried in the air , care being taken to shut outthe glare of the sun , in which the alga dry too soon ,
and become brittle . The method of successfully dryingin the air will depend upon the moistness or drynessof each climate . In Norway Kelps dried beautifullyon being exposed to the wind . To save Space
,one may
fold or roll up big alga,care being taken to do this
before they are too dry an d too brittle . They shouldafterwards be allowed to dry further . I t is absolutelynecessary to let Kelps dry before folding them up
,or
before putting the small ones into press for if put intopress at once they easily become mouldy . The driedspecimens can afterwards be moistened again thewater absorbed in soaking them out will be very easilygiven up in the press .
The plants to be pressed for the herbarium oughtto be carefully washed and sorted in sea water
,wherein
they retain their colours better than in fresh water .In a few cases it may be advisable to wash the alga infresh water before putting them into press . Travellerswill prefer photographic dishes for this sorting and thesubsequent spreading
,but collectors living near the
seaside will find common earthenware dishes , whitewithin
,preferable . For floating out the Specimens
,a
method of the late Mr . Holden is recommendable ,which I copy out of Professor Setchell’s paper .The utensils are Very sirnple—a shallow dish and arectangular piece of zinc , just a little smaller than thebottom
.
of the dish . The corners of the zinc (or twosides) are bent over at a sharp angle , all the same way .
The piece of zinc is then placed in the dish,with the bent
portions downwards,so as to raise the main portion of
the zinc somewhat from the bottom of the dish . Water
DRYING 1 59
is then poured in—fresh or salt , as the case may beuntil it is just the least bit above the surface of thepiece of zinc . Now take a piece of white paper or card
,
lay it with one surface on the zinc , and turn it over ,thoroughly wetting both sides . Then place the Specimen to be mounted , carefully cleansed, upon thepaper with the forefinger of the left hand gentlydepress the paper and zinc , until the specimen is floating freely . With the right hand Spread out the Specimen upon the paper , using a pair of needles or a softbrush to assist in the process . When finally spreadout
,gradually release the pressure upon the zinc
,
allowing it to rise and to drain off some of the water .Then gently lift the’
zinc until the whole of the Specimenis out of the water . When the paper is fairly dry
,but
before the alga has begun to show the effects , the specim en is to be placed upon a sheet of drying-paper, athin cloth is to be put over it , another drier upon that ,a specimen upon that , and so on . A flat board withsome stones makes a very good press better still is apress consisting of two iron fram es , with a network ofiron wire in the middle (Fig . and each frame provided with four little hooks . These little hooks arefastened together by four copper chains that can bemade shorter or longer , as circumstances require .
The chains must be fastened loosely, or only littleweight placed on the board in the beginning . Thespecimens may be pressed more strongly the secondday . I t is absolutely necessary to change the driersevery day, and it is better still to change them twicea day in the beginning .
For mounting the alga , white , unglazed , tough paperis the best the driers must be of pretty thick dryingpaper
,or Sheets of blotting paper . The cloth must be
a thin cloth or muslin , entirely free from starch . Most
1 60 THE PLANTSo f the finer specimens will adhere suffi ciently to paper
,
but the coarser ones must be afterwards fastened onto the mount with narrow straps of gurnm ed paper .
We have already said that blue alga must be Spread
FIG . 74 .—PRESS FOR DRYING ALGzE .
F IG . 7 5 .
—A RCH 1EOLITHO FIG . 76 .
—L ITHOPHYLLUM .
THAMN IUM .
out at once after having been collected . It is best tolet them dry in the air . Each specimen should beprovided with a label , on which must be mentionedthe locality where it was collected , the date , the nature
F IG . 7 7 .-HELIOSPH}ERA . (AFTER HERTW IG . )
CHAPTER V
THE FLOATING ANIMALS
BY THE ED ITOR AND E . T . B ROWNE
To those animals and plants which float in the sea,
whether at the surface Or in deep water,the term
Plankton is applied for brevity they are contrasted with the creatures which crawl upon ,
or arefixed to
,the bottom . In modern usage , Plankton is
generally taken to include even powerful swimmers ,such as fish and cuttle-fish, as well as helpless andminute organisms . The Animal Plankton alone formsthe subj ect of this chapter . Both figures and text giveonly sufficient detail to help the beginner in finding
P lankton ,from a Greek word m ean ing that which
is drifted ,
”the organ ism s dr iven about by the wind , tide ,
and current .
ABUNDANCE OF PLANKTON 1 63
out to what groups of animals his catch belongs .In order to find the real names of animals , or to lear nsomething of their structure and life-history
,the reader
must consult the ordinary textbooks and specialmemoirs cited . The figures in most cases have beena good deal simplified from their originals .
None but zoologists appreciate the wealth of animal
life in what appears to be clear , barren sea water .When one realizes . that the RightWhal e , 50 feet long,lives solely on Plankton , i t is easy to see that , as thePrince of Monaco pointed out many years ago , shipwrecked sailors adrift on boat or raft need never starve
,
if provided with a simple muslin net . Most groups ofinvertebrate or backboneless animals are representedin Plankton
,and the main types which ar e likely to
be captured at or near the surface will now be sketchedbriefly
,but
,it is hoped , sufficiently to enable anyone
to ascertain the group to which a specimen belongs .The exact position in the Animal Kingdom of eachform named will be found in the classification (p .
Animals are divided into two great subkingdoms,
according as they are composed of a single cell (Protozoa) , or of many cells (Metazoa) .Of the single- celled animals several gr oups occur in
Plankton,and are distingu ished for great beauty and
interest . Those which form a skeleton of lime (theForaminifera) are often represented in warm and temperate seas . The shell , into which the animal can becompletely withdrawn
,consists of successive chambers
,
generally more or less Spirally arranged , opening by amouth from the largest chamber , and al so perforatedall over by fine holes . From the chambers radiateextraordinarily delicate Spines of lime , which not onlyhelp to prevent the animals from sinking by increasingthe frictional resistance to the water , but also allow
1 64 THE FLOATING ANIMALSthe living matter (protoplasm) , flowing out of the Shellmouth and fine holes , to form a sort of bubbly latherbetween them , and to put out long threads for thecapture of prey (Fig .
Another group of unicellular animals (the Radiolaria) , in which the living matter has much the samecharacter , either form no skeleton , or form it of something else than lime . Thus , Thalassicolla i s a little ballof clear j elly with a dark kernel ; and Collozoum is acolony of similar animals , looking like little dots in acommon j elly ; these have no skeleton . But others
(Figs . 77 , 79 ,8 1 ) have beautiful skeletons of flint ;
in yet others (Fig . 80) the skeleton is formed of longneedles of a peculiar substance , radiating from acommon centre (Acanthom etra) . Lastly, in an oceanicgroup
,of which at present little is known , the skeleton
is very var ied in shape , and often of remarkable complexity and beauty (Figs . 82 toThe two closely allied forms , Ceratium (Fig . 38 ,
p . 1 22 ) and Peridinium (Fig . 41 , p . enclosed in acuirass of plates , often occur in very large numbers ;they are claimed by botanists as plants , but are alsoclassed by some zoologists as animals . Another form
,
often very common off our own coasts , is Noctiluca(Fig .
an important source of the luminosity or
so- called phosphorescence ,” which lights up the water
at night when disturbed .
Of marine unicellular animals which have no skeletonlittle is known
,for the reason that it is rarely possible
to study them alive on board, and practically impossible to preserve them properly for examination onshore ; consequently , careful drawings of “ such formsalive and expanded ar e greatly needed to thosepossessed of some zoological knowledge the naked
Ciliata and Flagellata may be commended .
1 66 THE FLOATING ANIMALS
FIG . 7 9 .—EUCY RTID IUM . (FROM LANKE STER ’
S ZOOLOGY ,BY PERM I SSION OF MESSRS . B LACK .)
FIG . 8o .—ACANTHOME TRA . FIG . 8 1 .
—STYLOSPIRA .
(AFTER HERTWIG .) (AFTER HERTWIG .)
UNICELLULAR A N IMALS 1 67
FIG . 83 .—Two SPEC IE S
OF CHALLENGERON .
(AFTER HAECKEL . )
82 .—C<ELODEND RUM . (AFTER
B ORGERT . )
F IG . 84 .—EUPHY SETTA .
(AFTER B ORGERT . )
FI G . 85—CONCHID IUM .
(AFTER B ORGERT . )
FIG . 86.—TUSCARORA . FIG . 87 .
—NOCTILUCA .
1 68 THE FLOATING ANIMALSOf the many- celled animals, the j elly-fish are among
the commonest and the most attractive .
Anyone not familiar with the classification of marineanimals would call any animal a j elly-fish which hasthe consistency and appearance of a j elly . But itis necessary to limit the name , even in its popularsense
,so as to exclude the swimming Urochordates
(pp . 1 84 which are most likely to be mistaken bythe uninitiated for true j elly-fish . The former are quitedifferent in shape and structure , and are nearly relatedto the Vertebrates (cf . Figs . 88- 100with Figs . 1 49The j elly-fishes may be separated for the sake of
convenience into four groups Hydromedusa,
(2) Scyphom edusa , (3 ) Siphonophores, (4) Ctenophores—each of which has well-marked characters . Thejelly-fishes belonging to the first two groups are commonly called Simply Medusa .
The Hydromedusae are small in size , seldom exceeding an inch in diameter
,and are caught by means of a
tow net . They may be subdivided into two groups :(1 ) Neritic or Shore forms ; (2) oceanic or blue-waterforms . The neritic forms occasionally drift out intothe ocean , but , as a rule , they become scarce beyondthe 100- fathom line .
The neritic Medusa (Figs . 88 , 89) are budded off
from small animals called zoophytes , ” or hydroids(Figs . 90 which form colonies , and are perman ently fixed at the bottom of the sea, or in some casesto floating obj ects . The hydr oids , which thus bud off
Medusa,do not develop eggs
,and are , therefore,
asexual . The little Medusa ,after leaving their
hydroids,begin an independent free- swimming career .
In the course of growth and development they usuallypass through a series of progressive stages , and finallybecome sexually adult . The eggs from the female
1 70 THE FLOATING ANIMALS
FIG . 88 .—PHIAL1D IUM . FIG . 89 .
—EUPHY SA .
(AFTER B ROWNE . ) (AFTER B ROWNE . )
FIG . 90.—PART OF COLONY THE HYD RO ID B OUGAINVILLEA .
Showingthe p olyp s with long tentac les , and the round or bell-shap edMedusa (jelly -fish) which are budded off from the co lon y whenadult . (From Lankester
’
s Treatise on Zoology , by p erm issio nofMessrs . B lack .)
JELLY-F ISH 1 7 1
FIG . 9 1 .—COLONY OF B OUGAINVILLEA FIG . 9 2 .
—OBELIA .{A
NTTACHED To A FLOATING B IT OF
Showing jelly-fish beingOOD ' budded at the sides ofa sp ec ial p olyp .
F IF . 9 3 .—RHIZOSTOMA . FIG . 94 .
—E PHYRA , OR Y OUNG(AFTER M ILNE EDWARD S . ) AURELIA . (AFTER D ELAP .)(Figs . 9 1 , 92 from Lankester
’
s Treatise on Zoology , by p erm issionof Messrs . B lack . )
1 72 THE FLOATING ANIMALS
FIG . 9 5 .—PELAGIA
.
(AFTER FORBES . )
FIG . 96 .—D IPHYES .
FIG . 97 .—B EROE . FIG . 98 .
-PHYSALIA B LA KE
.1 74 THE FLOATING ANIMALSshore . A few live deep down in the very cold zones ofthe oceans .The Siphonophores (Figs . 96, 98 to 100) are closely
related to the Hydromedusa , but most of them havenot the appearance of a j elly-fish . Although some arefairly simple in their construction
,others are extremely
complicated . They usually have the appearance ofa colony of animals composed of different kinds ofindividuals .
Thi s group contains some of the most beautiful,the
most delicate , and the most fascinating animals thatlive in the sea . They are typically oceanic animals
,
and keep afloat by the aid of air sacs or oil globules .Nearly all swim
,often at a good pace
,by means of
special organs called swimming bells . As a rule ,they
keep below the surface of the sea, and a few have beentakenat a very great depth . They are found all overthe world , even under the ice off the Antarctic contin ent, and the Species have usually a very wide geographical range .
Their life-history is very complicated , and in thecourse of development they pass through stages whichare not at all like each other , either in structure orgeneral appearance .
To the Siphonophores belongs the well—known Portuguese man- of-war (Physalia, Fig . This is thelargest Siphonophore , and it floats by the aid of anair sac at the surface of the sea . Its stinging power istremendous
,producing a maddening pain which lasts
for hours . Another common form is the little blueVelella (Fig . which also floats at the surface
,and
is not infrequently blown ashore .
Adult sea-anemones (Actiniaria) are rarely found inPlankton ; but larva of anemones which eventuallyaffix themselves to or burrow in the bottom , are fairly
WORMS 1 75
common near shore,and one , at leas t , is found on the
high seas north and west of Britain (A’rachnactis
,
Fig .
The group known as Ctenophora, from their comblike paddles
,is common ; Pleurobrachia (Fig . 102) may
be taken off our own coasts ; with its two graceful tentacles , i t plays its prey exactly as an angler plays asalmon . Cestus, or Venus ’ s girdle (Fig . is aninhabitant of warmer seas . Beroe (Fig . a glovefinger of pink j elly, al so occurs off our coasts .The various groups of flatworms are rarely met with
in Plankton ,and consequently should be carefully pre
served if found . But the group of roundworms(Cha topoda) , to which belong the common earthworm ,
and the ragworm and lugworm beloved of sea—anglers ,require mention . Near shore swimming larva ,
whichultimately grow into crawling or burrowing adultworms
,are frequent at some seasons ; Fig. 104 shows
some of the simpler forms . Many are provided withlong bristles
,such as give the name to this group
bristle- feet Of adult forms , perhaps the commonest is Tomopteris (Fig . sometimes 2 inches long .
Of the Nereids or ragworms , some are occasionally captured near shore
,appar ently at the breeding season .
Of the curious Syllid worms (Autolytus) some reproduce asexually by forming a second or even severalheads in the course of the body
,and then dividing into
as many worms as there are heads .Of the wheel- animalcules (Rotifera) , so common in
fresh water , some seventy species are stated to bemarine little is known of them .
The little glass- arrows , or Cha tognatha, are of constant occurrence , apparently in all seas they vary inlength from 5 inch to 4 inches (Figs . 105 ,
The group to which crabs, lobsters, and so forth
1 76 THE FLOATING ANIMALS
FIG . IO3 .—TOMOPTER I S . (FROM THE CAMBR IDGE NATURAL
H I STORY , BY PERM ISSION OF MESSRS . MACM ILLAN . )
FIG . IO4 .—TYPES OF CHE TOPOD LARVZE .
From left to right Mitraria , Nerin e , Po lygord ius , Cha topterus .
FIG . 105 .—SPADELLA . FIG . IO6 .
—SAGITTA .
’
1 78 THE FLOATING ANIMALSbelong—the Crustacea—are probably more plentifulthan any other in Plankton . Of the water—fleas(Cladocera) , minute animals with two shells , a largepair of rowing antenna , and one large eye , some are
not infrequently taken (Evadne , Fig . Anothersubdivision of Crustacea, also with two shells , is termedthe Ostracoda
,one family of which is sometimes
very abundant (Con choecia,Figs . 108,
Probably the most widely spread and prolific groupof the whole Animal Kingdom , so far as Plankton isconcerned , is formed by the oar- footed Copepoda
(Figs . 1 10to 1 1 2 ,which are only very rarely ,
if ever,
absent from a haul generally minute , they are activeswimmers they have been met with in such abundanceas to give the sea a reddish tinge . When magnified ,
many Show brilliant colourings , due either to iridescence (Sapphirina, Fig . 1 1 4) or to the presence of d10psof coloured fat . Many of the fish- lice belong tothis group ; some are only temporary parasites , and
can swim (Fig . 1 10) others embed themselves in theflesh of fish and other creatures , and become so altered ,in adaptation to a paras itic existence , that only a
study of their development Shows them to be Copepods ,or, indeed , Crustaceans at all . The Barnacles , orAcorn- shells (Cirrhip edia) , are not properly planktonic ,but may be found attached to floating weed, driftwood
,etc . These have free- swimming larval stages ,
enclosed in two shells,like an Ostracod .
The subdivision of Crustacea,which includes the
sand- hepper and the so- called fresh - watershrimp (theAmphipoda) , although far more plentifulon the bottom
,has representatives (Fig . 1 1 3 ) in the
Plankton . Some of them haunt the bells of j elly-fish,
presumably for protection ,while others (Phronima ,
Fig . 1 1 5) establish themselves in the hollow skin‘of
1 80 THE FLOATING ANIMALSDoliolum (see p . Very closely allied to these isthe subdivision which includes the common wood- liceor pill-bugs these are not insects
,as is generally
thought , but belong to the subdivision Isopoda theym ay generally be distinguished from the previous subdivision by being flattened from above downwards
,
while the former are flattened from side to side . Fewof them occur in Plankton on the high seas
,except as
parasites, either temporary or permanent (Fig .
Rather unexpectedly , considering their Size and weight ,some of the Stomatopoda may be found swimmingnear shore (Fig . 1 1 9) they should not be handled ,
astheir big claws , shutting like a pocket-knife , can cuta finger to the bone .
The Opossum- shrimps (Schizopoda) , so calledfrom the brood-pouch present in some species
,are fre
quently taken . Several have special luminous organs ,provided with lens and reflector , in different parts oftheir bodies (Fig . The subdivision
,which includes
the lobster and shrimp , is termed Macrura—thelong- tails few of these are planktonic when adult
,
but some prawn- like forms are widely found . Mentionmust be made , however, of the curious little Sergestids
(Fig . not only because they are often captured,
but also because of their curious larva (Fig . Lessadapted to a swimming life are the Brachyura
,or
Short-tails , of which the common crab is a membersome can swim a little , and one at least has been foundin quantity about 200miles from Shore over very deepwater . Crabs are also found attached to gulf-weedand other floating obj ects .The larva of Crustacea are often even more numerous
than the adults . Most marine Crustacea hatch out of theegg in the form called a Nauplius , which may be knownby a Shield- shaped body,
a Single eye , and three pairs
THE FLOATING ANIMALSof limbs (Figs . 1 20,
This larval stage moults orsheds its Skin repeatedly
,not only growing
,but also
changing its shape somewhat at each moult,until it
attains the parent form .
Many of the higher Crustacea, after passing throughthe Nauplius stage , gradually attain a Zoe’ a stage ,which may be recognized by the limbs of the fore-partof the body having Sprouted
,by a pair of large eyes
having appeared , and by the tail part of the bodyhaving grown out the latter carries no limbs
,
except sometimes the last pair (Figs . 1 22
A few families have special larva ,which are often
common near Shore after the breeding season . Thusthe crawfish,
or Spiny lobster (Palinurus) , passesthr ough the remarkable stage Phyllosoma (Fig . 1 28)the crabs
,after their zoea stage , assume the form
known as Megalopa before tucking in their tails
(Fig . 1 27) and the Stomatopoda have a set of larvapeculiar to themselves (Fig . 1 25 ,
Of the group to which oysters,snails, and cuttle-fish
belong,theMollusca, some subdivisions occur inPlan kton .
The oyster - forms,or Lamellibranchs , possessing two
shells,are occasionally represented by larva (Fig .
The snail- forms,or Gastropoda , are frequently met .
J anthina,a warm-water snail
,sometimes thrown on
our western shores,has a purple shell ; to its foot is
attached a raft,on the underside of which the eggs are
embedded . Atlanta (Fig . 1 3 1 ) has a Spiral shell , with anarrow keel Carinaria
,like a transparent slug , carries
a Shell on its hump (Fig . 1 3 2) very like it , but withoutshell or hump
,are several other warm-water forms .
The pteropod,or wing- footed forms, are found in all
seas of these the maj ority have shells (Figs . 1 3 3 ,
Near-shore larva of Gastropods are often plentiful ;the most characteristic is the Veliger stage (Fig .
CRUSTACEANS—MOLLUSCS 1 83
FIG . 1 28 .
—PHYLLOSOMA . (AFTER FIG . 1 29 .
—SERGE STE S LARVA .GARD INER . ) (AFTER CLAU S .)
FIG . 1 3o .—LUCIFER . (AFTER CLAUS . )
The cuttle-fishes , of which the octopus and squid aretoo well-known to require a figure
,are all more or less
planktonic , although many, especially in shallow water ,are bottom feeders ; they sometimes attain a huge size .
Some have a web between the arms,which thus form
a great funnel . Any forms with an external shell(except the familiar Pearly Nautilus and Argonauta)should be carefully preserved for study by experts,such as the body of the little Spirula,
the dead Shellsof which are not uncommon in Eastern seas .
The r ight S ide of this figure is of the dorsal or upp er
surface ; on the left S ide is drawn the ven tral or under surfac eto Show the l im bs .
1 84 THE FLOATING ANIMALS
Of the group oi Echinoderms—the starfish ,brittle
Stars,sea-urchins , trepangs, sea-lilies—a single adult
genus only has as yet been taken in Plankton,but their
larva are frequently captured ; these are
’
even moreunl ike their adult form than in the Crustacea . Theadult form in Crustacea was attained by a series o fmoults
,but in the Echinoderms it rather grows out
of the larva , which , so to speak ,Shrivels down on to it .
Each of the five subdivisions has its own type of larva ,
four of which are here shown (Figs . 1 40 toOf the enormous group of Insecta,
only one smallfamily is truly planktonic (Fig .
Of the Polyzoa (theyhave no English name) none arefound in Plankton
,except accidentally attached to
drift wood or weed . Near shore their larva are common -
of these,the most likely to strike the eye has a
shell like a flattened funnel (Fig .
The foregoing groups are all taken from the invertebrate animals
,but there remain some creatures ,
very common in Plankton,which only a naturalist
would dream of classing anywhere near vertebrates .Yet these animals
,both by structure and development ,
are undoubtedly akin to vertebrates they have (amongother characteristics) , either when larval or throughoutlife , a supporting rod in the back (the notochord) ,exactly like that of a sturgeon or lamprey, or thesimilar rod round which the vertebra are moulded inthe embryos of all vertebrates
,including Man . The
names of these groups refer to this notochord .
The sea-squirts and salps are included in thegroup Urochordata—i. e with the notochord in thetail . Some of them retain it throughout life ; forinstance
,Appendicularia which can often be
captured in this country in an estuary on a flowingtide some species form temporary houses of j elly
'
1 86 THE FLOATING ANIMALSlike material . Others drop the tail and notochord onassuming the adult form of these Pyrosoma (Fig .
brilliantly luminous , as Its name fire-body implies,
is a colony of animals embedded in a common cylinderof jelly , mouths outwards . A solitary form
, Doliolum ,
FIG . 140. FIG . 1 4 1 . FIG . 1 4 2 . FIG . 1 4 3 .
FIG . 1 44 . FIG . 1 4 5 . FIG . 1 46 . FIG . 1 47 .
FIG . 1 4o .—AURICULAR IA LARVA OF A HOLOTHUR IAN .F IG . 1 4 1 .
—THE SAME LATER, THE YOUNG TREPANG SHOWING .FIG . 1 4 2 .
—PLUTEU S LARVA OF AN E CH INOID .FIG . 1 4 3 .—THE SAME LATER , THE YOUNG SEA -URCHIN PROM INENT .
F IG . 144 .-B IP INNAR IA LARVA OF AN ASTERO ID .FIG . 1 4 5 .—THE SAME LATER , CARRYING THE YOUNG STARFI SH .FIG . 1 46 .—PLUTEUS LARVA OF AN OPHIURO ID .FIG . 1 47 .—THE SAME LATER , WITH THE YOUNG B RITTLE -STAR .
(Mod ified from Johannes Muller . )
is remarkable for its complex life-history ; the form ,A ,
(Fig . 1 50) itself developed from a fertilized egg , givesrise to little buds
,which wander up on to the proj ecting
horn behind their parent,and arrange themselves in
three rows . Those of the side rows , B , grow into aspoon-shape
, and act as food and water pumps for the
SALPs 1 87
rest (Fig . 1 5 1 ) large buds of the middle row , C,presently
break off (Fig . carrying on their broken stumpstiny buds
,which also belong to the middle row . These
FIG . I4S .—APPEND 1 FIG . 149 .
—PYROSOMA B LAKECULAR IA . (AFTERLOHMANN )
FIG . I 50.—D OLIOLUM . FIG . I 5 I .
—D OLIO FIG . 1 52 .
—DOLIOLUM .
A1 .—The nurse form LUM ' C .
—The wanderingwhich buds B , C ,D . B .—The spoon form . form carryingbuds
of D .
FIG . 1 53 —D OLIOLUM . FIG . 1 54 .—SALPA . FIG . 1 5 5
—SALPA .D .—The sexual form . The sexual form The budd ing formwith a chain Of little
salp s hanging out .
grow up into the sexual form,D (Fig . and break
away in their turn ; their eggs begin the cycle anew .
Even more complex,and not yet fully understood , is
1 88 THE FLOATING ANIMALSthe life- cycle in two similar forms . Specimens of allsuch from tropical seas should be carefully preservedfor study by competent hands .
Another subdivision is represented by Salpa . Inthis
,an animal which has developed from the egg
,buds
off a chain of little Salps ; first the chain,then the
separate individuals are detached , become sexual , andproduce eggs, and the life-history begins again
(Figs 1 54 , 1 55)A second group is formed by the Hemichordata,
inwhich the notochord is only partly developed ; noneare planktonic
,but one (Balanoglossus) has a plarik
tonic larva , which is not uncommon .
Lastly,in the group Cephalochordata (Amphioxus) ,
in which the notochord extends to the tip of the head,
the adult , in shape rather like a fish ,lies half buried at
the bottom , but the larva are planktonic .
Excluding the fish , which are the subj ect of a separatechapter, the animals above described may be taken torepresent fairly completely types of the forms whichare likely to be captured at or near the surface .
The next question is,how to catch them . The net
in ordinary use,termed a tow net , consists of the
frame,the net
,and the tin . The frame is best made
as follows : From an oil-shop procure a thin 1 8- footlength of flexible cane
,such as is used to poke down
stepped drains a sharp bend in it may be taken outon soaking the bend in boiling water . When straighttwist this up into a circle of 5 feet in diameter , andlash the ends in with strong cord or copper wire . Thenet is best made of Swiss Silk (boulting- cloth) , such asis used for sifting fine flour a useful all- round sort has
1 96 THE FLOATING ANIMALSminutes
’
haul is generally enough ; after this the netshould be hauled in very gradually
,otherwise the
pressure of the inside water against the meshes damagesthe more delicate animals terribly .
Nets of the above pattern can be convenientlyworked down to 100 fathoms when out of soundingsand so far as the present writer ’s experience goes
,far
more animals and far more kinds of animals will becaptured at 50, 75 , or 100 fathoms than at the actualsurface . For this work are required a little handwinch of the simplest kind , and rather more than100 fathoms of flexible wire sash- line (such as is usedfor heavy windows) , to the end of which a 20-poundlead is attached (soft copper sash- line
,inch circum
ference,breaking strain about 200 pounds , price about
36S .,-but see also the lines given on pp . 277 ,
278 underYacht Equipment) . Put an eye in the free end of thewire to carry the lead , and taking this as 100 fathoms ,mark off backwards 75 , 50, 25 , and o fathoms, as beingrecognized depths for study . The nets can be thenstropped on to the wire at any of the depths required
,
but not more than two should be used at a time .
I f it is impracti cable to °
fix up a winch and work atthese depths
,still observations should not be confined
to the comparatively barren surface . To the ordinary20 fathoms of tow rope fix a 1 o-pound lead ; attachthe nets well above the lead , and tow at 5 ,
10,or 1 5
fathoms below the surface if the water allows of it ;if not
,tow about a half fathom above the bottom .
As soon as it arrives on board ,the contents of the
tin Should be emptied , with plenty of extra water, intoa big glass bottle—a wide-mouth pickle- j ar or sweetj ar is excellent . The larger animals can be pickedout with a lifter (an old tablespoon , the bowl bent atright
'
angles to the shank ,serves the turn) . For those
NERITIC AND OCEANIC 1 91
of smal ler size , take a glass tube , about 8 inches longand inch outside diameter , hold this between thumband middle finger , stopping the upper end firmly withthe first finger lower it thus over the animal
,remove
the first finger,and animal and water will rush up into
the tube . Replace the finger , and the tube with itscontents can be lifted out if kept vertical . Theanimals can thus be transferred to glass dishes and exam ined ,
or preserved for future study (see Chapter XL) .In temperate climates most planktonic animals will
live for some time in a glass bottle if absolutely cleanand kept cool . In the tropics , where the bottle cannotbe kept cool , they die very soon , and should be preserved as soon as possible .
For immediate examination on board , as a ship israrely still enough (except in harbour) to allow of theuse of a microscope , a small dissecting microscope
,
”
with simple lenses magnifying about 6 and 10
diameters,is absolutely invaluable .
Naturally enough , the animals in Plankton are notalways and everywhere the same . In the first placethe distance from Shore makes a great difference .
Plankton from shallow water near land shows numerouslarva of bottom animal s
,and such j elly-fish as are
budded from hydroids , but over deep water suchlarva are hardly ever present there are larva ofplanktoni c adults
,blit they are not so numerous in
proportion,an d these adults are mostly different from
those near Shore . Hence we distinguish the neritic,
or coast—wise Plankton,from the oceanic , or blue
water Plankton ; the 100- fathom line may be roughlytaken as the boundary between them
,but they pass
imperceptibly in to one another . Secondly, the temperature of the water makes a great difference in thePlankton it is fairly obvious that as a rule an animal
1 92 THE FLOATING ANIMALSwhich can stand arctic cold of 30
° to 3 5° F . will not
be happy in the tropics with a sea temperature of80
° to 90° F . (al though such cases are said to exist) ;
but many marine animals seem to be influenced byquite small differences in temperature . Thirdly
,if there
be too little salt in the water—for example,in estuaries
or the Baltic—many species will not live there . Lastly ,
the character of the Plankton al ters a good deal withthe depth it is not every animal which can thrive inabsolute darkness , at a very low temperature , on suchcasual food as falls from the surface layers towards thebottom .
This last statement Opens up a fresh branch of thesubj ect . Plan kton is by no means confined to theupper layers of water, but has been captured even atthe greatest depth to which suitable n ets have beenlowered to fathoms) . Such nets
,termed
closing nets ,”
are lowered to a.
known depth , withthe mouth closed they are then opened by mechanicalmeans, towed either vertically or horizontally for aknown distance , closed again , and brought closed tothe surface they therefore only contain animals fromthe desired depth . This mid-water work has beensystematically attempted only of late years
,and forms
a fascinating branch of study . Very little is knownat present about the Plankton of great depths, andany yacht with a steam winch can do most valuablework in this direction . A description of the necessaryoutfi t is rather beyond the scope of these pages, butdetails can easily be obtained from the ChallengerSociety . Many of the animals from great depths seemto be confined to deepwater, but some are known alsofrom the surface .
Of one branch of Plankton we know almost nothingthat is , of those invertebratesw hich, al though capable
194 THE FLOATING ANIMALSirregular figure in three dimensions , with length ,
breadth , and thickness . Unfortunately, in the presentstate of knowledge , we are unable to draw this figurewith certainty for any single species hence it will bereadily understood how important it is always torecord the temperature of the water from which a haulis made
,and, if pract icable , also the salinity .
One interesting result of the ability of many an imalsto live below the surface , provided that they keep abovetheir minimum temperature , is that some arctic speciesare continuously distributed from pole to pole in thedeep cold water of mid- ocean ; but have never beencaptured anywhere near the surface in the tropics
,where
the temperature is above their maximum .
It has been stated (and it appears to be true for greatlakes, and to some extent for Shall ow water such as theEnglish Channel) that the greater part o f the Planktoncomes to the surface only by night , and sinks to somedepth by day as a protection against too bright light .Like many other accepted statements , this stands inneed of accurate testing as regards the open ocean .
Anyone becalmed in a sailing ship , or hove to in a yacht ,could gather valuable info rmation on this point bysystematic day and night surface hauls in or near thesame position . Still more valuable information wouldbe yielded by similar day and night hauls at differentdepths . This opens up two new questions—how toget a basis for comparison of different hauls , and howto deal with subsurface hauls which are hardly deepenough to rank as mid-water hauls .
Hauls m ay be readily compared if standardizedthat is to say ,
if they are made with nets of similarmouth , length and mesh , for the same time , and at the
same speed of towing . In this case all that is necessaryis to preserve the whole catch , and to count the
OBSERVATIONS WANTED 1 95
specimens of any species under study ; thus it can bereadily shown in accurate terms that a species is rareat the one hour , depth , date , or place , and common atthe other . Every haul made for comparative work(and that is pre- eminently the work now required)should be made with standard nets , time , and speed .
The only thing difficult of control is the speed ,except
in a small launch , but this can be read by a currentmeter (p . 53 Standards are suggested on p . 1 99 .
As a rule , the greater number of the species capturedat or near the surface at any particular position at seawill be found to extend to about 100 fathoms at thatposition (not necessarily elsewhere , where the temperature and other conditions may be different) . For aproper study of the alleged up
- and-down movementsof the Plankton , and for many similar obj ects , i t isdesirable to know , not only whether i t is rarer or moreabundant at the surface under certain circumstances
,
but also where it goes to when not at the surface .
The method of hauls with open nets at various depths
(p . 1 90) will throw a good deal of light on this,but
they are not to be trusted absolutely , because theycatch specimens from higher levels while being hauledto the surface . For accurate work a closing netshould be used horizontally, lighter and smaller thanthose used for true deep mid-water work ,
so as to beworkable by hand with the smal l reel and strandedwires already mentioned they should carry the samestandard net , and be used for standard time and atstandard speed .
Other points requiring study by similar methods arethe supposed movements of Plankton due to rain
,
breaking . seas,wind
,fresh water from large rivers
,
floating ice,and so forth .
A curious feature well worth attention is the way in
1 96 THE FLOATING ANIMALSwhich Plankton becomes concentrated into swarms orstreaks it is by no means un iversally distributed
,even
over a small district . Such streaks should be surveyed,
if possible for dimensions both horizontally andvertically . Particular attention should be paid tothe comparative abundance of plant food inside andoutside the area , as well as to their position as regardscurrent and tide , for it has been suggested that theyare formed exactly as a river throws raffle on itsbanks .
All special adaptations of a planktonic organism toits conditions of life should be noted . A strikingseries of these adaptations is naturally directed towardspreventing weak swimmers from sinking . This obj ectis attempted in various ways , of which the chie f areeither (a) a diminution o f weight by the formationinside the animal of light fluids (in the bubbles of
Foraminifera and Radiolaria) , fats (Copepoda) , j elly
(j elly-fish and salps) or gas (Siphonophores) or (b) anincrease of surface in order to increase the friction infalling through the water , produced either by flatteningthe body (Phyllosoma , Sapphirina) or the growth oflong spines (Foraminifera; Crustacean larva ) .Coloured sketches from life are always valuable away
from home waters . Most of the larger invertebratePlankton is nearly colourless and transparent , and any
exceptions to this should be noted , and ,if possible
,
sketched .
O f late years the Pla nkton has been used , in conn ection with the International Investigation of theNorth Sea and Adj acent Waters , as a means oftracing out the derivation of the body of water inwhich it occurs , and as an indication of the amount ofavailable fish- food for this purpose most attention hasbeen paid to the minuter animals and plants (micro
1 98 THE FLOATING ANIMALSI t will be seen readily from this brief sketch that
plenty of interesting work awaits anyone who hasopportunity and a tow net . In harbour
,from a pier
or reef of rocks if the tide serves,from a small boat or
a big ship , the tow net can be streamed with thecertainty of an interesting result ; even if the catchbe scanty , the result becomes of value if the reason forits scantiness be found . No observation ,
howeverapparently insignificant , is scientifically worthless if itbe securely based on fact . On however small a scale ,valuable work m ay be done for science without attacking the more intricate problems . The simple tow-nethaul in foreign parts , if accompanied by the necessaryobservations , will always be worth making ,
preserving ,
and submitting to experts for report .Finally , a word of advice to the beginner who wishes
to collect for his own instruction , and to do seriouswork ; he will be at first bewildered with the wealthof life at his disposal , and depressed with the difficultyof finding what is already known , what not . Let
him therefore confine himself strictly to the animalsof one
,or at most two
,groups
,and hand the rest over
to an expert at home let him select for his own studya group which has been recently revised , or dealt within a report from some important expedition , so that hemay get the literature of the group under control .The choice of the group will depend to some extenton the waters to be traversed
,but in this , as in all such
matters , the Society will be glad to advise .
NOTE .
—A s it m ay he lp the begin ner to have standards for
op en tow n ets suggested to him , on e of the wr iters subm its his
own sp ec ification ,which does n ot d iffer greatly from the n ets
in u se gen eral ly on exp edition s Net : C ircum feren ce of
m outh , 5feet ; c ircum feren ce at tin ,
1 foot ; length , 6 feet ;m eshes p er l in ear in ch ,
62 breadth of top an d bottom tapes ,
1 3 in ches . (2 ) Cane fram e , in s ide d iam eter , 1 8 In ches . (3 )
STANDARDS 1 99
B r idles, 2 feet 6 in ches long. (4) Length of hau l , 20 m inutes .
5 ) Hor izon s for shallow work , surface ,and 25 , 50, 7 5 , an d 100
fathom s , with occas ional hau ls at 1 50 fathom s . This wr iter ’
s
n ew hor izontal c losing n et takes the sam e S ilk n et as the
can e fram e , an d the resu lts of the two can there fore read ilybe com pared .
1 56 .- CESTUS OR VENUS ’S G IRD LE . (AFTER CHUN . )
CHAPTER VI
THE S E A F LOOR
BY SIR JOHN MURRAYMethods.
—The oldest method of sounding was bymeans of the hand- lead , usually 1 2 to 14 pounds inweight , armed with lard or tallow , to which asample of the bottom adheres
,and with a line marked
in fathoms and fractions of a fathom . Practicallyall the coasts of the world have been surveyed byinstruments of this kind used from rowing-boats .When attempts were made to sound in 100 or 200
fathoms , heavier weights and more carefully preparedhempen lines were employed , and the leads were provided with cups, valves , or snappers , to bring upsamples of the sands , gravels , and muds . Sir J amesClark Ross , during his Antarctic cruise (1 839 to
made most praiseworthy attempts to soundthe greater depths of the ocean with ordinary soundinglines and heavy weights from small boats . He
succeeded in recording depths down to fathoms,
but, although the time each 100 fathoms left the reelwas noted in the usual way , he was uncertain
‘
whenthe weights reached the bottom , and the results werenot al together trustworthy . About the year 1 854Lieutenant Brooke , of the United States Navy , introduced the method of detaching a heavy weight fromthe sounding- tube on its striking the bottom henceforth deep soundings were recorded much more fre
200
°
202 THE SEA FLOOR
F IG . 1 57 .—B A ILL IE SOUND ING MACH INE A S USED ON B OARD
H .M .S . CHALLENGER .A In elevation ; B in section . The heavy weights , e ,
drive thecen tral tube , a ,
In to the bottom dep osit , and the ooze is retain edin the tube by the butterfly valve , f. As soon as the susp en sionis relaxed
,the shou lder carry ing the wire which ho lds up the
heavy weights becom es sheathed ,the wire and weights be ing
left on the bottom .
SOUND ING 26 3
various types of wire sounding machines , such as theLe B lan e ,
the Sigsbee , and the Lucas . The Lucasmachine (Fig . 1 98 ,
p . 282) is the one most frequently inuse , and is extremely satisfactory . I t seems unnecessaryto describe these
'
various instruments in detail ; theirgreat advantage is that they indicate at once whenthe weight strikes the bottom . In well- appointedcable ships soundings in fathoms can be madein an hour from start to finish , but in order to do thisthe wire must be hove in as fast as possible
,and
breakages of the wire frequently occur . One cannot,
therefore,work at this rate with any regard to the
safety of instruments attached to the wire . Withhempen line the maximum rate of working can beobserved , even when the line carries instruments .
On cable ships there is usually plenty of old or damagedwire , and where the depth only is required , this old wireis sometimes used and cut adrift when the bottom hasbeen reached in order to save the time of heavingit in .
A great many arrangements have been used with thesounding apparatus to bring up samples of the depositsforming on the bottom in deep water . The armingof the hand- lead with lard and tallow has already beenmentioned snappers , cups , and tubes with valves arealso used for this purpose . Experience alone canShow the best appliance to adopt in special circumstances . On board the Challenger
,when sounding
over Red Clay areas,the Baillie sounding tube, 23
inches in diameter , without butterfly valves , has b eenforced from 1 8 inches to 2 feet into the deposit , and hasbrought up a section of that depth
,the total quantity
of clay being more than enough to fill a quart bottle .
So far as obtaining a sample of the bottom is concerned when sounding
,this is the most successful
204 THE SEA FLOORrecord . Sometimes , however , the whole of the mudwould slip out of the tube while being hauled up . Toprevent this , valves and balls at the upper end of thetube were used with varying success . In positionswhere a typical Globigerina Ooze was expected ,
abutterfly valve was generally inserted in the lowerend of the tube , and this arrangement was generallysuccessful in retaining some of the deposit . To placethree or four small tubes side by side , without valves ,has been found a good arrangement . Gravel andsmall stones are the most difficult of all samples torecover , and for these the snapper (Fig . 1 99 , p .
and the Rendle tube are the most success ful .During the Michael Sars Expedition (1 9 10) a
heavy contrivance of Nansen ’
s was successfully usedto bring up a section of the deposit
,but this entailed
a stranded wire and a separate sounding Operation .
In the dredge and trawl large quantities of thedeposits were sometimes brought to the surface , anda careful examination of these threw a great dealof light on the samples procured by the soundingmachine . Large samples of mud , ooze , or clay, werecarefully passed through wire sieves (Fig . 1 58) withdifferent sized meshes
,and these coarse and fine
washings were carefully preserved for futureexamination . It has often been regretted that largersamples procured in the dredge were not preservedand brought home without being passed throughSieves .
The samples of deep- sea deposits which are procured are best preserved by being at once placed inwide-mouthed glass- stoppered bottles , and a smallquantity of methylated spirit can be with advantageadded , although this is not essential . Cork- stopperedbottles and tubes can also be used . Spirit , added to
THE SEA FLOORo f our knowledge in this respect , for if the extentof the ocean be great , it should be remembered thatthe uniformity o f the conditions is also great overwide areas . Notwithstanding the great number o f deepsea soundings recorded Since 1 895 , when the depthhemispheres in the final volume o f the Challenger ”
Reports were published , it is somewhat remarkablethat the contours shown on these have been coni
paratively li ttle altered in their broad general outlines ,although many deeps and submarine elevations havebeen discovered in recent years , and in some regionsthe contour- lines now present a much more complicatedappear ance .
These depth-hemispheres have been kept up todate by Sir J ohn Murray and Mr . J . G . Bartholomew .
An inspection of the reduced chart given here willShow at a glance where deep soundings are mostabundant .
The greatest depth yet recorded in the ocean isfathoms metres) , or 66 feet less than
six English miles . This was a sounding taken bythe US S . Nero in the Challenger Deep to thesouth of the Ladrones , Where the Challenger ”
recorded a depth o f fathoms . Depths greaterthan fathoms are also known in the AldrichDeep in the South Pacific . There are altogether tendeeps in which depths exceeding fathoms havebeen recorded , two of these being in the A tlantic , andthe remainder in the Pacific . The term deep is
limited to those parts of the ocean in which soundingsof fathoms or deeper have been taken . On thedepth-hemispheres above referred to , fifty-seven deepsare now shown—thirty-two in the Pacific , eighteen inthe Atlantic , five in the Indian Ocean ,
and two in theSouthern Ocean south of latitude 40
°
S .
CONTINENTAL SHELF 26 7
From the data at present available the depths overthe total floor of the ocean are now estimated as
follows
B etween the shore line and the 100- fath . line, 7 p er c en t .
100-fatli . 1 000 92 000 1 9
5 8
Over fathom s 7
I t Will be seen from the above that the extent ofthe sea-bottom lying between the shore line and a
depth of 100 fathoms (600 feet) is very nearly equalto the area lying between 100 fathoms (600 feet) and
fathoms feet) . The first area is known as
the continental shelf, and is regarded as belonging tothe continental areas . Many portions of it wereevidently dry land at no very remote geologicalperiod . Deep ravines frequently cross the continentalShelf, and are believed to be submerged river valleys ,which in some cases can be associated with still existing rivers—for instance , the Rhine and the Congo .
The materials which cover the continental shelf areto a large extent under the influence of wave
’
s , tides ,and currents , and are constantly subj ected to transport by these agencies . It is believed that waves orcurrents do not transport other than the very finestparticles at depths greater than 100 to 1 50fathoms (600to 900 feet) . In cup- shaped depressions
,or sheltered
bays within the 100- fathoms line , fine mud may be deposited in relatively shallow depths , but on coasts facingthe great ocean basins muddy deposits commence toform at an average depth of 100 fathoms . Beyondthat depth the whole floor of the ocean may be re
garded as an area of deposition . We have as yet noevidence of transport by currents at these greater
3208 THE SEA FLOORdepths .
* The area between 100 fathoms and the next
900 fathoms , it will be observed , covers only 9 percent . of the whole floor of the ocean . This area iscalled the continental slope. I t represents the sidesof the ocean basins , and shows a relatively rapiddescent into deep water ; it is the only ar ea of theocean
’
s floor which can be regarded as concaveupwards .
Beyond fathoms the floor of the ocean becomesmore and more flat and uniform
84 per cent . lies below fathom s ,
65
and 7
These great submerged plains Sink , as we haveseen , in some instances to depths of nearly six Englishmiles , and at times they are interrupted by cone- likeelevations , some of which do not rise to the surfaceof the ocean , while others do , and then form groupsof volcanic or coral islands . Although a great manysoundings have been recorded exceedingfathoms, and a great many submarine elevations havebeen also recorded in recent years, still the generalresult of recent explorations has been to increase thearea of the ocean lying between and
fathoms .
Deposits on the Floor of the Ocean .—We have very
few indications of the nature of the solid rocks formingOn the Wyville Thom son R idge , between the North of
Scotland and the Faeroe B ank , m ud is n ot dep os ited at dep ths
of 250 and 300 fathom s . The tidal wave , be inghere confined ,
apparently sweep s the top of the r idge at these great depths ,
and we have eviden ce of the sam e phenom enon on the saddlebacks between contiguous ocean ic islands , and on very deep lysubm erged ridges . Further observation s in this direction are
m uch desired .
216 THE SEA FLOOR
1 . Materials o f all kinds borne to the ocean by rivers,
winds , and floating ice , as well as what is torn from thecoasts by waves , currents , and other agencies ; theseare termed terrigenous or earth born .
2 . Materials derived from volcanic eruptions,both
submarine and subaerial . Volcanic dust is transportedimmense distances by the wind . Pumice of varioustypes is worthy of special notice , because its areolarspongy structure , containing cavities filled with gas ,admits of very wide distribution
,by dri fting on the
surface of the ocean .
3 . Materials of extra- terrestrial origin,which have
fallen to the earth from interstellar space,such as
cosmic spherules of iron and nickel,and chondrites
with lamellar structure .
4 . Materials of organic origin m ay be carried to theocean by rivers and winds , but the chief source is thehard parts—the shells and skeletons—of organismswhich live in the surface
,intermediate
,or bottom
waters of the ocean . These m ay be composed of lime
(calcium carbonate) , such as calcareous Alga ,Fora
m in ifera, Corals , Alcyonarian and Tunicate spicules ,worm tubes
,Ostracod and Cirriped shells , Echinoid
spines,shells of Molluscs
,Polyzoa , bones of fishes and
whales,etc . ; or they m ay be composed of flin ty
(siliceous) spicules and frustules , such as Diatoms ,Radiolarians , and Sponge spicules . In these organicremains it is important to distinguish between thosewhich belong to floating or Plankton organisms , and
those which belong to bottom- living or Benthosorganisms . Generally Speaking ,
it has been found thatthe remains of Plankton organisms predominate in thedeposits of deep water far from land ,
and the remainsof bottom organisms predominate in the deposits ofShallow waters near shore .
SECONDARY PRODUCTS 2 1 1
5 . In addition to the foregoing there are many substances which m ay be termed chemical or secondary products . Clayey matter , which arises fromthe decomposition of pumice , felspars , and otherminerals on the sea floor , may be regarded as asecondary product so also may the manganese nodulesso abundant in some Red Clay areas , where the lapilliand bombs of basic rocks thrown out by volcanoesabound the palagonite and zeolitic materials found inthe Red Clay may be placed in the same category . Inaddition
,greensand (glauconite) grains , glau con lric
casts of calcareous organisms , phosphatic cqncretions,sul hate of barium nodules , iron and calcareous concretion s , must be classed among the secondary productsnow forming in the deposits on the sea bed
,many of
them thr ough the intervention of decaying organicmatter and bacteria .
The varied materials just enumerated are distributedvery unequally over the floor of the ocean . Theterrigenous materials are most abundant along theshores of continents and islands , and in all enclosed andpartially enclosed seas . The geological structure ofthe adj acent land-masses determines the generalcharacter of the deposits along the shores and in theshallower waters
,especially as regards the inorganic
constituents . The deposits off Coral-reef shores are,
of course,chiefly made up of fragmentary particles
derived from the growing reefs . The size of thefragments diminishes
, as a rule , as the distance fromthe shore line and the depth of water increase ; but thisis not always the case , for in the very centre of thePacific and in very deep water rounded fragments ofpumice have been obtained of all Sizes, up to more than1 foot in diameter . Again , in regions now, or inrecent geological times , affected bv floating ice , large
21 2 THE SEA FLOOR
boulders and varied rock- fragments have been fre
quently dredged up hundreds o f miles from land . I tis known that seals and penguins may transport rockfragments in their stomachs to great distances . Forthese
,among other reasons , the size o f the particles is
of little use for the purpose of the classification o fmarine deposits .
While the detrital matter from continents and islands,
and the shells and skeletons of bottom- living organisms,
prevail in the deposits near shore and in shallow water,
the remains of pelagic or Plankton organisms,and
chemical or secondary products , prevail in all the deepwater deposits far from land . I t is a remarkable fact
,
however,that in areas where the depth is fathoms
or deeper , hardly a trace of calcareous pelagic shells ,such as those of Foraminifera and Pteropods
,is to be
found in the deposit , although thes e m ay be met within great abundance in an adjacent area where the depthis only or fathoms . In like manner theSkeletons of Radiolaria and the frustules o f diatoms arenot nearly SO abundant in some deposits as would beexpected from the numbers captured in the surfacewaters of the region . Both calcareous and siliceousremains are dissolved by sea water , and when they are
not Specially abundant in the surface waters , they m aybe very rare in , or wholly absent from , the deposits atthe bottom . At other times these remains of pelagicorganisms appear to be almost entirely masked by the
terrigenous materials , or other organic remains , formingthe deposit .
From the above considerations it is evident that thematerials which go to form marine deposits vary innature , abundance , and size , according to the structureof the nearest land , the character of the submarinevolcanic eruptions
,the distance from the shore line ,
2 14 THE SEA FLOORfounded on the dominant element or characteristicaspect of each type of deposit , and attempts to bringinto prominence their origin and constitution . Thereis no Sharp line of demarcation between the differenttypes they all shade the one into the other
, and it isoften difficult to determine what name should be givento a deposit on the border line between two or threetypes .
* For the information of the geologist,physical
It is essential to be continually on on e’
s guard again stsources of error when exam in ing deep
-sea dep osits . The
obj ect in view is to arr ive at a true n otion of the compositionof the dep osit as it lies at the bottom of the sea . Som etim es
the trawl or dredge m ay com e up filled with fu lly a ton of
m angan ese n odu les , or large and sm all fragm en ts of pum ice ;therem ay be hundreds of Sharks ’ teeth m ixed with dozens of
ear-bon es of whales . Som e of these m ay have l iving Lep asor Hydro ids , or Serpu la , or Foram in ifera , attached to them .
It has som etim es been supp osed that the whole deposit wasc om p osed of these rem ain s ; it is ,
however , alm ost certainthat these var iou s Obj ects were em bedded in c lay
,which
passed through the m eshes of the n ets . The sam e m ay be
Observed with re feren ce to the phosphatic and glaucon iticn odu les found in relative ly deep water along c on tin en talshores . In using sounding tubes with butterfly valves , a
large p rop ortion of the fin er p arts of the depos it is som etim es
washed out while the tube is being hau led in ,and the larger
calcareous organ ism s app ear to be m ore abundan t than theyreally are . When a large quan tity of dep osit is brought upin the dredge or trawl , and p assed through sieves , the var iouscon stituents are separated , and the d ifferent p ortion s haveoccasion ally been descr ibed separately ; in this way havear isen erroneously the n am es Orbu lina ooze , B ilocu l in a c lay ,and Copro litic m ud . In l ike m anner the fin er p arts of a
R adiolar ian ooze have been descr ibed as D iatom ooze , and
the coarser p arts of a D iatom ooze as Radiolar ian ooze .
When the dep osit is preserved in water or sp ir it , the sam p leis sorted in to d ifferent layers by Shaking if a p ortion be takenfor descr iption from the upp er layers , and another from the
lower layers in the bottle ,widely d ifferen t resu lts will be
Obtain ed .
The best sam p le for descr ip tion is that which is taken
DESCRIPTION OF DEPOSIT 2 1 5
geographer , and others interested in marine deposits ,it is specially important that descriptions should giveas near ly as possible the proportions of the variousconstituents of which the deposit is made up, as wellas the size of the mineral fragments . This , it isbelieved , can best be accomplished by the methodadopted in describing the Challenger collections , as
set forth in the following model
H.M.S. Challenger .Station 3 3 8 . March 2 1
,1 876 .
Lat . 2 1 1 5’
S . Long.,1 4
°2’ W .
D ep th fathom s .
Globigerina Ooze.—White , with slight rose tinge ,
granular,homogeneous
,resembling chalk when dry .
CALC IUM CARBONATE (92 -54 per - Globigeri
nida , Pulvinulina (80-00 per cent . ) Miliolida ,Textu
larida ,Lagen ida ,
Rotalida ,Nummulin ida per
otoliths of fish, Gasteropods , Lamellibranchs ,Pteropods , Heteropods
,Lepas valves , Ostracods ,
E chinoderm fragments , Polyzoa , Coccoliths , Rhabdoli ths ( 1 1 -54 perRES ID UE (74 6 per —Reddish-brown .
Siliceous Organisms (1 -00 per —Sponge sp i
cules , Radiolaria , imperfect casts of Foraminifera ,Astrorhizida , Lituolida ,
a few Diatoms .
d ir ect from the sounding tube ,an d it shou ld be n oted whether
the sam p le is taken from the sup erfic ial or the deeper layers .
With the kn owledge we n ow p ossess it is p ossible for an exp ert
to tell ap p roxim ately the latitude ,longitude ,
and depthfrom which a dep osit has been p rocured . When ,then ,
a
sam p le bears a label showing a Globiger ina ooze ,for in stan ce ,
from a dep th or latitude wh ich does n ot accord with exp eri
en ce ,it ra ises su sp ic ion s of m islabelling. This has frequen tly
oc cu rred with sam p les labelled on the corks ,which have been
interchanged .
'
2 16 THE SEA FLOORMinerals (1 -00 per —Mean diameter 006mm
angular felspar , hornblende , magnetite , magneticspherules , pumice , a few manganese grains , bronzitespherules .
Fine Washings per —Amorphous matter ,with small mineral particles , and fragments of scoriaand siliceous organisms .
REMARKS—This is one of the purest Globigerinaoozes obtained by the Challenger , and is almostwholly composed of the dead shells of surface organisms .
A few pumice fragments were found in the washings ofa large quantity of deposit .
When carbonate of lime is present , the shells andother calcareous organic fragments are determined bymicroscopic examination . The lime is then removedfrom the sample by weak hydrochloric acid , and therelative percentages of lime and residue can be approximately estimated by inspection
,or determined by a
simple analysis . The nature an d relative abundanceof the clayey matter
,mineral particles , and remains
of Siliceous organisms in the residue can be estimatedby microscopic examination . A description of thiskind can quite easily be carried out on board ship .
The following is a short description of the prin cipaltypes of deep-sea deposits :
A .—Pelagic Deposits.
1 . Red Clay.—This deposit is the most characteristic ,
and probably the most widely distributed , of all deepsea deposits over the ocean ’s floor
,covering a very large
portion of the deeper parts of the Pacific . The name issufli ciently expressive of the nature and appearance ofthis type of deposit
,there being always a considerable
51 8 THE SEA FLOORdecomposition . These manganese nodules vary inform and size in different localities at one place they
m ay be large,subspherical ,
and smooth , resembling a lotof potatoes at another placesmaller , like marbles at
another place large and
spherical , but the externalsurfaces rough to the touch
,
owing to the numerous m am
m illation s (Fig . 1 59) at
another place flattened withone side rougher than theother ; and at yet anotherplace the nodules take theform of huge slabs . With themanganese nodules are usuallyassociated , especially in deepwater far from land , numerous
F I G 1 59 .
—S C A L P E L L U M F IG . 1 60.—SPHERULEW ITH METALL IC
ON A MANGANESE NODULE NUCLEUS COATED wrrH‘
B LACK(“ CHALLENGER MAGNETITE ,
SUPPOSED TO BE OFCOSM IC OR IG IN ( CHALLENGERteeth of sharks and ear-bones of whales , impregnatedand coated more or less thickly by the peroxides ofiron and manganese . In the Red Clays , also , numerousminute magnetic spherules (Fig . some with
OOZES 2 1 9
metallic nuclei , have been met with , and have also beenextracted from the manganese nodules after these havebeen broken up in a mortar these spherules are sup
posed to have fallen from interstellar space , and are
hence called cosmic spherules . In some positions ,agam , there are small zeolitic crystals (phillipsite) , asindividuals
,twins , stellate groups , and spherulitic
aggregations these are supposed to be secondary products , formed in situ
,aris ing from the decomposition
of the basic volcanic particles present in the deposits .
Red Clay is estimated to cover an area of aboutsquare miles (or square kilo
metres) about square miles in thePacific Ocean
,about square miles in the
Atlantic Ocean,and about square miles in the
Indian Ocean .
_2 . Radiolarian Ooze.—This deposit is distinguished
by the abundance of the Skeletons of Radiolaria , andis found typically in very deep water in the tropicalregions of the Pacific and Indian Oceans . I t isotherwise Similar to the Red Clay j ust described , andmay contain a few Shells of pelagic Foram in ifera andsmall angular volcanic mineral particles , fragmentsof _ pumice , augite , felspars , hornblende , magnetite ,volcanic glass
,frequently altered into palagonite , as
well’
as manganese nodules , Sharks’ teeth , and ear
bones of cetaceans .
Radiolarian Ooze is estimated to cover an area ofabout square miles (01 squarekilometres) —i.e about square miles in thePacific Ocean , and about square miles in theIndian Ocean .
3 . Diatom 0oze.
-This deposit is distinguished bythe prominence of Diatom frustules (skeletons) , and istherefore characteristic of those regions in which
THE SEA FLOOR
these pelagic plants swarm in the surface waters,
as in the extreme northern part of the Pacific,and
far south ln the neighbourhood of the Antarcticcircle . The skeletons of Radiolaria and the Shells ofone or two species of pelagic Foram in ifera are usuallypresent , as well as continental mineral particles andice-borne rock fragments , Since this deposit occursgenerally within the regions affected by floating ice
(Fig .
In some of the Red Clays and Radiolarian Oozes ofthe Central Pacific the frustules of the large DiatomCoscinodiscus rex are so abundant that the deposithas sometimes been described as a Diatom Ooze .
Diatom Ooze is estimated to cover an area of aboutsquare miles (01
.
square kilometres) -principally in the Southern Ocean ,
with asmal l area in the North Pacific Ocean .
4 . Globigerina Ooze.
—This deposit is named fromthe predominance of the dead Shells of Foraminifera,which lived in the surface waters of the ocean , thegenus Globigerina (Figs . 78 , 162 ) being the most characteristic , though the representatives of other generaare usually present in the tropics (Fig . Associated with the Shells o f pelagic Foraminifera are theshells of pelagic Molluscs (Pteropods and Heteropods) ,pelagic calcareous Algae (COCCOSpheres and Rhabdospheres , or their broken fragments—Coccoliths and
Rhabdoliths) , as well as the remain s Of calcareousorganisms
,which habitually live on the bottom
"‘
of thesea , such as Molluscs , Echinoderms , Annelids , Corals ,Polyzoa
,and bottom- l iving Foraminifera . The remains
of Siliceous organisms (Radiolaria , D iatoms , and Spongespicules) may generally be detected ,
and a few smallmineral particles , such as felspar , augite , hornblende ,magnetite , and volcanic glass , with a small quantity of
FIG . 1 6 1 .—D IATOM OOZE . (AFTER CHUN , FROM K RUMMEL
’
S
OCEANOGRAPH IE , BY PERM I SSION OF J . ENGELHORN’
S VERLAG IN STUTTGART . )1 -5 , Cosc inodiscu s ; 6, Asteromphalus ; 7 , Fragilaria an tarctica ;
8 , 9 ,Syn edra ; IO , Rhizoso len ia ; I I , Chaetoceras ; 1 2 , Navi
cula I 3 , Dictyocha I4 , a broken Radio larian .
F IG 1 62 .
—D EAD SHELLS O F GLOB IGER INA , THE SPINES OF WHICHHAVE BEEN '
D I SSOLVED IN THE IR FALL To THE B OTTOM(“ CHALLENGER
OOZES 223
F IG . 1 63 .—GLOB IGER INA OOZE , CONS I STING LARGELY OFFORAM INIFERAN SHELL S B LAKE
FIG . 1 64 .—PTEROPOD OOZE , CONSISTING MA INLY OF PTEROPODAND FORAM IN IFERAN SHELLS B LAKE
These figures were originally taken from the ChallengerRep orts .
224 THE SEA FLOOR
B .
—Terrigenous Deposits.
6. Blue Mud.—This deposit is the one most fre
quently met with in the deeper waters surroundingcontinental land and in enclosed and partially en
closed seas . It is prm cipally composed of materialsderived from the disintegration of continental land
,
consisting largely of the fragments and mineralsof continental rocks (the older crystall ine and schistocrystalline rocks , quartzites , sandstones and limestones) of various dimensions , but usually larger nearshore and smaller as the deep sea is approached
,
except in the regions affected by floating ice .
‘
Quartzis the characteristic mineral species , associated withorthoclase and plagioclase felspars , green hornblende ,mica, etc ; glauconite is usually present , but not insuch abundance as in the Green Mud . There is usuallya considerable proportion of amorphous clayey matter
,
increasing in amount with increasing distance fromland
, SO that some of the deeper samples have adecidedly clayey aspect , but the deposit , as a rule
,
may be described as earthy rather than clayey . In somesituations the remains of bottom- living organisms maybe present in considerable numbers , and in others theremains of pelagic organisms m ay be so abundant thatthe deposit resembles a Globigerina Ooze .
Blue Mud is estimated to cover an area of aboutsquare miles (or square kilo
metres) .
7 . Red Mud.-This is a local variety of Blue Mud ,
hitherto known only from the Yellow Sea in thePacific
,and off the Brazilian coast in the Atlantic ,
characterized by the presence o f a large quantity ofreddish ferruginous matter brought down by the largerivers in the Vicinity .
10. Coral Mud.—This deposit occurs off coral
islands and coral reefs , and is chiefly made up offragments of organisms living in the Shallow watersand on the reefs , such as calcareous Algae , Corals ,Molluscs , Polyzoa , Annelids , Echinoderms , and Foram in ifera . In the shallower waters near the ree fsthese calcareous fragments are larger , and the morefinely divided calcareous matter is less abundant
,than
in the deeper waters further removed from the reefs ;the deposits are then called Coral Sands. These deposits m ay contain , at times , much volcanic material .Coral Mud is estimated to cover an area of about
square miles (or square kilometres) .
General Remarks.
The Black Sea is far removed from the great oceans ,and its deeper water is cut off by submarine barriersat the Bosphorus from the Mediterranean , which inits turn is cut Off from the Atlantic by an additionalbarrier at the Straits of Gibraltar . Vertical circulationis much restricted by this and by the fact that thesurface layers are often
_much less saline than thedeeper layers ; hence the deeper waters of the BlackSea become more or less saturated with sulphurettedhydrogen ; no living organisms (other than bacteria)are met with in depths greater than 100 fathoms .
Amorphous carbonate o f lime is precipitated from thewater of the Black Sea ,
and makes up a considerablepart of the deposits now in process of formation thisis the only place where this is known to occur in theseas of the present day . In all partially enclosed seas
-like the Mediterranean and the Red Sea—circulationis generally cut Off by submarine barriers , and thisresults in thermal and other conditions which are
CONTINENTAL BORDER 227
less favourable to organisms than the conditionsexisting in the open ocean . The deposits in thoseseas which interpenetrate the continental masses areterrigenous in origin , although there m ay be an
approach to pelagic conditions towards the morecentral parts .
I t has already been observed that the continentalshelf facing the great oceans is continually swept bywaves
,tides , and oceanic currents , down to an average
depth of 100 fathoms . Just beyond this depth all
the minute mineral and organic fragments from thecontinental shelf come to rest on the bottom
,and
form what I have called the mud line . This constitutes the
'
great feeding ground of the ocean . Largenumbers of Holothurians and other marine creatureshere eat the m ud to obtain the organic matter associated with it . Indeed , i t is more than probable that allmarine deposits are in this way passed through theintestines of organisms . Very many Crustaceansfrequent this area to pick up the little particles oforganic matter which are j ust settling on the bottom
,
and some of them—like NyctiphaneS —are providedwith phosphorescent organs to enable them to do thismore effectively . All these mud- eating creatures arein turn the prey of carnivorous animals , both vertebrateand invertebrate .
The continental slope extends from the m ud line
(100 fathoms) down to the mean sphere levelfathoms) The continental Slope , and Similar
areas around oceanic islands, present a greater varietyof conditions than is found elsewhere on the ocean bed .
I f all the e levated p ortion s of the earth’
s crust were cut
away , and filled into the ho llows till the whole sur face wasun iform ,
then the who le earth wou ld be covered by an ocean
fathom s in dep th—the m ean sphere leve l .
'
228 THE SEA FLOOR
At the upper limit the sun ’s rays may produce twilight,
but elsewhere there must be total darkness,except
where this is relieved by the phosphorescent light oforganisms . The temperature conditions are likewisewidely different at the upper and lower limits of theregion . At some points the descent from the 100
fathom line is known to be almost perpendicular at
other points outcrops of stratified and volcanic rocksare indicated .
The deposits now being laid down over the contimental Slope vary greatly according to position . Offlarge rivers they are chiefly made up of detritus fromthe land ; at other places, especially where cold andwarm currents alternately occupy the surface , pelagicconditions are more or less pronounced
,and greensand
and phosphatic deposits are being laid down ; quartzand other continental minerals predominate . Generallyit may be said that in enclosed seas , and along thecontinental Shelf and Slope , deposits are being formedquite Similar to those which have made up the stratifiedrocks of past ages . Indeed , it seems as if inland seasand the borders of continental masses had again and
again been pushed up into dry land, and again and againbeen torn down and transported to the ocean by thesame denuding and disintegrating agents , the finalresult being that quartz particles accumulate on thecontinental areas , rendering these rocks Specifically
r than the deposits on the oceanic areas .
In the abysmal regions,beyond the dep th ~
of themean Sphere level , covering about one-half of theearth ’
s surface, the physical conditions are uniform
and widespread ; the temperature everywhere ap
proaches zero Centigrade the darkness is relieved onlyby phosphorescent light motion of all kinds must beextremely Slow
, and there is little evidence of transport
THE SEA FLOOR
areas,especially the border regions , are the most
unstable .
From a recent examination of some Challengerdeposits sent to him from the Challenger Office
,
Professor J . J oly has been able to give the radiumcontents of deep- sea deposits . He finds that the RedClays and Radiolarian Oozes contain much moreradium than the Globigerina Oozes or terrigenous deposits in fact , the radium content is greatest wherethe rate of deposition is believed to be the least . Theidea at once suggests itself that this is connected withthe greater amount of cosmic dust in the deep depositsfar from land . This is well worthy of the attention ofthose who in future m ay dredge up large samples o fdeposits from the Red Clay areas .
CHAPTER VI I
ANIMALS OF THE SEA FLOOR
BY W . T . CALMAN AND G . P. FARRAN
IN dealing with the fauna of the sea bottom it isnecessary to make use of some convenient and naturalclassification of the subj ect . I t has long been recogn ized that , in passing from the Shallow water surrounding the Shore to the abysses of the ocean , we find manystriking changes in the character of the inhabitantsassociated with the increasing depth ; and a classifi
cation based On the depth at which the animals live isa more or less natural one . While those areas or zonesof depth which are commonly accepted are markedout , rather on account of their physical features thanbecause they possess separate faunas Sharply definedfrom each other , still the assemblage of animals foundin each zone , taken as a whole , differs considerablyfrom those of the other zones , and may convenientlybe dealt with apart from them .
The zones of depth usually distinguished in Europeanseas are based on those originally defined by EdwardForbes in the middle of the last century . These werethe Littoral Zone
,the Laminarian Zone , the Coralline
Zone , and the region of Deep -Sea Corals . For the lasttwo may be substituted the Continental Shelf and theContinental Slope , and to the list m ay be added theocean floor , a region which in Forbes
’
s day was believedto be devoid of living inhabitants , but which more
2 3 1
232 ANIMALS OF THE SEA FLOOR
recent research has proved to have a varied fauna .
These zones must be taken as applying primarily tothe Shores of the North Atlantic and the Mediterranean
,
but with some small alteration will be found to holdgood for many other seas .
The Littoral Zone , or the space between high andlow water mark ,
is dealt with elsewhere in this volume
(Chapter I t is necessarily inhabited by a faunawhich is able to endure a certain amount o f periodicexposure to the air . At its lower limit it passes intowhat is known in European waters as the LaminarianZone , taking its name from the oarweed or Tangle
(Laminaria) , which , with other seaweeds , is its moststriking feature . It extends to a variable depth ,
usually less than 1 5 fat homs . Though the name
Laminarian is somewhat restricted in its application ,
yet the physical characters of this zone m ay be recogn ized almost universally . These m ay be summed upas the penetration of sunlight
,and the consequent
presence of abundant vegetable life in the form ofbrown and red seaweeds the exposure to violent waveaction which may stir up sediment
,and the lowered
salinity from the surface drainage of the land even inthe absence of any large rivers . I t is in this zonethat we must look for the maj ority of the vegetablefeeders of the sea
,with the exception of those which
live upon minute floating diatoms and Similar organismsof the Plankton .
Below the region in which the brown seaweedsflourish
,or (speaking very roughly) from 1 5 fathoms
downwards , lies the region which we now deal withcomprehensively as the Continental Shel f .As a general rule the land-masses of the globe are
surrounded by an area of comparatively Shallow water ,varying in extent
,which has been called the area of
234 ANIMALS OF THE SEA FLOORin temperature are rather seasonal and gradual thandiurnal or rapid , and are not dependent immediatelyon the alterations of the temperature of the air . Themean temperatures in various regions Show
,of course
,
Very great differences .
The salinity , l ike the temperature , is locally fairlyconstant , the changes being Slow,
and the range com
paratively small , though great differences may benoticed between different seas . The light is verymuch diminished , passing from a dim twilight in themore shallow parts to complete darkness in the deeper .
The actual depth to which light can penetrate dependsvery much on the clearness and freedom from sedimento f the water ; but it may be taken that at depthsexceeding 100 fathoms practically no light can be received from above , while at depths considerably lessthe amount of light is SO small as to have little influenceon life .
The absence of light entails the absence of plant lifeand consequently of vegetable feeders , with the except ion of such forms as subsist on microscopic floatingvegetable matter . The greater part of the area istoo deep to be troubled by wave action , and theforce of tides and currents is much diminished . Thebottom is fairly uniform over large areas , though theactual types of bottom do not differ materially fromthose found immediately adjommg the Shore , thematerials of the sea floor in both cases being
‘
derived
from the débris of the adj acent land . I t is usually thecase that the composition of the bottom becomes fineras the depth and the distance from Shore increase , butthis is by no means a universal rule , gravel , rocks , andstones being often met with even beyond the edge of theContinental Shelf . The water overlying this zone
CONTINENTAL SHELF 23 5
contains in suspension a quantity of organic andmineral matter derived from the Shore .
Taken as a whole , the area from low-water mark tothe edge of the Continental Shelf possesses a faunawhich is perhaps richer and more varied than that ofany other area on the surface of the globe . A catalogue Of its inhabitants would include all the chief typesof invertebrate animals (except the air-breathingArthropods) and many fishes . I t would be impossiblewithin the Space at our disposal to attempt even an outline sketch Of this fauna and Of its variations in differentparts of the world
,but for the guidance of those um
familiar with zoology a few of the commoner typesrepresented in the illustrations may be mentioned .
Sponges (Porifera) often form a conspicuous part ofthe contents of the dredge or trawl in waters of moderatedepth
,and deserve the attention of the collector
,not
only for their own sake , but also on account of thenumerous Crustacea , worms , and other animals whichburrow in them or shelter in the crevices . In passingfrom shallow to deeper water the Shapeless encrustingsponges of the littoral region are replaced , in part atleast , by types of definite and often beautiful form(Fig . This is especially the case with the glassSponges (Hexactinellida) , of which the well-knownVenus ’s Flower-basket is an example .
Below the depth at which true seaweeds flourish thedredge is often filled with masses of what the fishermanor t rawler terms weed ,
” but which the zoologistrecognizes as plant- like animals . Even for the zoologistit is not always easy to distinguish by the unaided eyebetween the feathery tufts of Hydroids (Figs . 90, 9 1 ,
1 67 ) and the much more highly organized Polyzoa . B e
longing to the same division of the animal kingdom
(Coelenterata) as the Hydroids are the sea-pens,or
ANIMALS OF THE SEA FLOOR
F1G.1 65 .-HOLTEN IA , A D EEP - SEA GLA SS SPONGE CHALLENGER
ANIMALS OF THE SEA FLOO'R
FIG . 1 67 .—CLADOCARPUS , HYD ROID ( B LAKE
CONTINENTAL SHELF 39
FIG . 1 68 .- PENNATULA , A SEAPEN
F IG . 1 69 .—GORGON IA , A SEA -FAN .
F IG . I 7O .—GORGON IA , SHOWING
THE POLYP S IN CONTRACTIONAND EXPANSION . (FIGS . 1 69
AND I 70 FROM LANK E STER’
S
TREATISE ON ZOOLOGY , BYPERM I SSION OF MESSRS . B LACK . )
ANIMALS OF THE SEA FLOORurchins (Fig . and their kindred are abundant inall seas . Belonging to the same group (Echinodermata)are the sea- cucumbers , trepangs , or Holothuroidea(Fig . and the feather- stars (Crinoidea) , some of thelatter free- living like the Antedon of our own seas
,some
attached by a stalk like the stone- lilies of earliergeological epochs (Fig . These stalked crinoids
,
confined for the most part to fairly deep water , wereformerly among the most prized rarities of zoologicalcollections , though the progress of deep- sea explorationhas now rendered them tolerably familiar .
Under the name of worms are included very manyanimals of widely dissimilar appearance . The Planarians are mostly flattened leaf—like forms , often ofbrilliant colours , which glide smoothly over the surfaceof ston es or shells . The Nemertines may be recognizedby their soft , very extensile bodies , and their longthreadlike proboscis , which can be completely withdrawn within the animal . They are frequently richlycoloured and of very varied form , some slender and ofimmense length , others Short and thick and veryfragile , breaking up into small fragments on the leastprovocation . Burrowing in mud or clay we find theEchiuroids, or Spoon-worms , and the Sipunculoids thelatter with tough leathery bodies , blunt at the tail ,and tapering to a small proboscis , which, as in theNem ertin es, can be withdrawn into the body like thefinger of a glove which is turned inside out .By far the most important and numerous group of
worms is that of the bristle-worms , or Polychaetes,which are to be found practically everywhere in saltwater (Fig . They carry stumpy, footlike lobesbeset with bristles along each Side of the body, bymeans of which they crawl or Swim , and breathe bygills which are either Situated on the lateral lobes , or
242 ANIMALS OF THE SEA FLOOR
FIG , I 7 I .—SALENIA
, A SEA -URCHIN CHALLENGER
SEA-CUCUMBER 243
F IG . I 72 .-A SE A -CUCUMBER OR TREPANG CHALLENGER
°
244 ANIMALS OF THE SEA FLOOR
(Entomostraca) . I t is perhaps not out of place tosuggest here that , in order to capture these smallerforms
,the water in which dredged material has been
put to s tand Should be strained off through a pieceof fine Silk . Of these Entomostraca , but very unlikethe rest in appearance , are the Cirripedes , includingboth the stalked bam acles and the sessile acornshells . The stalked forms are for the most partfound growing on floating obj ects , but there is onegenus (Scalpellum) with a Short stalk
,which is often
found in deep water attached to Hydroids or otherfixed obj ects (Fig . 1 59 , p . The sessile or acornbam acles are most abundant between tide-marks orin Shallow water , but there are a few deep- sea specieswhich reach a very large S ize . Of the other Entom ostraca , the Branchiopods belong to the Plankton
(Chapter but the Copepods and Ostracods havemany bottom representatives .There are two very large groups of Crustacea , num
bering some thousands of species, which we m ay conveniently illustrate by the sandhopper and the woodlouse . These are the Amphipods (Fig . 1 80) and theIsopods (Fig . They may be found everywhere
,
and may,for the most part , be recognized by their
resemblance to the types above mentioned . Onesection of the Amphipods , however , the ghost Shrimps ,or Caprellids , differs very markedly from the rest .The Caprellids may be recognized by their SlenderSkeleton- like bodies , their thin legs, the two front pairsof which are armed with strong claws
,and their
looper - like movements (Fig . 1 9 1 ,p .
The Cumacea , another group of small Crustacea,living for the most part buried in mud
,may be known
by their small nut-shaped bodies and their long slendertails ending in a fork .
ANIMALS OF THE SEA FLOOR
pass for pebbles , and usually frequent ground where thebottom is of coarse gravel .
F IG . I 7 3 .
—OPHIURA A B RITTLE STAR CHALLENGERThe sea Spiders , or Pycnogonida, are easily recog
nized by t heir resemblance to the animals from which
MOLLUSCS 247
they take their English name . In most species thesmall body scarcely affords room for the attachmentOf eight (very rarely ten) long Slender legs
,but in a
few cases the legs are Short and stout as,for instan ce ,
in the common Pycnogonum li ttorale , which, in Spiteof its name , is Often found in moderately deep water .Most of the Pycnogons are of smal l or moderate siz e ,but in some deep-water Species the legs may span alength of feet .
F IG . I 74 .—A RCHASTE R ,
A STAR-F I SH B LAKE
The commoner forms of the Mollusca, at any rate ofthe shelled Species , are familiar to everyone , but thereare some Shell- less species , and others with peculiarshells , which call for Special note . The usual type ofGastropod , as exemplified by the whelk or periwinkle ,bears an asymmetrically coiled Shell , but there is reasonto believe that the earliest forms of molluscs weresymmetrical . This symmetry is still found in theChitons , in which the Shell is made up of eight plates,
248 AN IMALS OF THE SEA FLOOR
overlapping as in an armadillo or wood- l ouse (Fig .
Allied to the Chitons is a very remarkable group ofmolluscs
,in which the shell is entirely absent . These
are for the most part wormlike in form, and are usually
found tightly coiled round the branches of Hydroidsand Al cyonarians .The nudibranchs , or sea- Slugs , are Shell- less gastro
pods , which externally appear to be symmetrical .
They start life , however , in a minute coiled shell . Onesection of them , the Dorididae , in which the gills arearranged in a circle on the hinder end of the animal ,are found in their greatest development , both in numberand Size , in tropical seas , where , both along the Shoreand in Shallow water , they attract attention by theirlarge Size and brilliant colours . Another section , theEolididae , in which the gills are not concentrated onone spot , but scattered as papillae all over the body ,
are , on the contrary, very poorly represen ted'
in warmseas , but are richly present on our own coasts (Fig .
The Lamellibranchs,comprising such molluscs as
the oysters , mussels , cockleS , scallops , and so forth , aretoo well known to need further mention .
Among the Cephalopods , the Octopus and its all ies
(Fig . with eight equal arms and a rounded body ,must be , distinguished from the squids and cuttle-fish,
which have ten arms,one pair of arms being much
longer than the rest . The paper Nautilus belongsto the first of these groups . The second includes a
great variety o f forms—some Short and squat , likeSepia
, Sepiola ,and the cuttle-fish,
others elongatelike Loligo and the squids (Fig . The pearlyNautilus belongs to a group apart from all the rest . I tis the sole representative of a once very abundantOrder
,to which theAmmonites , so well known as fossils ,
also belonged . Most of the Cephalopods can swim
VARIOUS 25 1
forms often encrust stones in large Sheets . They arestrangely degenerate animals , for they begin life as freeswimming , tadpole- like larva ,
which approach somewhat to the Vertebrates in their structure .
F IG . I 77 .- SERPULA
,A TUBE-DWELLING F IG . I 78 . AMPHI
B RISTLE-WORM . (FROM THE CAM NOME , A B RISTLEBRIDGE NATURAL H ISTORY , ” BY PER WORMM ISSION OF MESSRS . MACMILLAN . )
252 ANIMALS OF THE SEA FLOOR
As regards the geographical distribution of theanimals inhabiting moderate depths , it m ay be said ,
speaking very generally , that the character of the faunais determined rather by temperature than by geogra
phical position . Thus it is found that genera andeven species of animal s, which m ay be dredged at a
depth of a few fathoms in the Arctic regions,occur at
greater depths in the more southern parts of theirrange
,where the Shallow water is too warm for them .
For example , a certain starfish which is found comm only Off the west coast of Ireland between 300 and
400 fathoms , and which stretches as far south as theBay of Biscay in deep water, occurs at a depth of1 5 fathoms within the Arctic circle . Again ,
the currentof relatively cold water which runs northwards alongthe west coast of South America allows many of thesouthern types to extend far to the north
,and carries
the characteristically subantarctic Isopod genus Serolisto the coasts of Southern California .
I t is possible to divide up the Shallow water of theglobe into regions whose faunae differ from each other ,both in the actual Species which compose them , andalso in the general proportion in which the variousgroups of the animal kingdom are represented . Thusit is found that the fauna of the Shores of East Africahas a much closer resemblance to that of India and ofthe Pacific than it has to that of South or of WestAfrica . Similarly, the fauna of the north-east coastof the United States has more species in common withthat of the western Shores of Europe than with thatof the West Indies . In a recent work (Ortmann ,
Grundz iige der Marinen Tiergeographie the coastalwaters of the globe , down to 100 fathoms , have beendivided into a number of faunistic regions which maybe briefly mentioned here .
254 ANIMALS OF THE SEA FLOOR
The definition of these regions must not be takenas implying that there is any strict demarcation
F IG . I 7 9 .—ROCINELA , AN F IG . I 8o .
—EPIMERIA ,AN
ISOPOD AMPH IPOD (“ B LAKE
F IG . I 8 I .—CATAPAGURUS ,A H ERM IT-CRAB , ITS POSTER IOR END IN
A SHELL , ON WH ICH L IVES A COLONY OF ANEMONES B LAKE
between their faunae . There is naturally a great deal ofoverlapping , and very many Species are common to two
FAUNISTIC REGIONS 255
or more regions ; for example , a large number of thecommon marine animals of the British Isles are to befound in the Mediterranean , often -at increased depths .
F IG . I 82 .
—MUNIDA , A GALATHE ID B LAKE
A more detailed subdivision Of the seas , on much thesame lines as that
'
of Ortmann ,but including oceanic
bottom areas, and suitable also for plan ktonic areas , has
FIG . 1 83 .-WILLEM <E SIA
, A D EEP-SEA LOBSTER OF THE FAM ILYE RYONID JE CHALLENGER
258 ANIMALS OF THE SEA FLOOR
F IG . I 84 .-CHITON .
F IG . I 8 5 .—E OLI S , A SEA - SLUG . (FIGS . 1 84 AND 1 85 FROM THE“ CAMBR IDGE NATURAL H I STORY , BY PERM ISSION OF MESSRS .MACM ILLA N . )
F IG . 1 86 .
-B ENTHOTEUTHIS, A DEEP- SEA SQU ID BLAKE I
) .
VARIOUS 259
F IG . 1 8 7 .
—ELEDONE B LAKE
FIG . 1 88 ,
—CE LLULAR IA ,ON E OF
THE POLYZOA B LAKE
0
FIG . 1 89 . CE LLULA R IA ,MAGNIFIED
FIG . 1 90.
—TEREBRATULA,A LAMP
SHELL CHALLENGER
260 ANIMALS OF THE SEA FLOOR
necessarily made from a distance , can appreciate .
The reason for the preference for one type of bottomrather than another usually resolves itself into aquestion of support or of Shelter , either for the Speciesitself or for its prey . Of course , there are very manyspecies that may be . found indifferently on all sorts ofbottom and under all kinds of conditions .The connection between the nature of the bottom
and its inhabitants may be illustrated by an example .
In some Spots on the west Side of the Irish Sea,when
a haul of a trawl is made , at least 90 per cent . of thecatch consists of the Alcyonarian or false coral
,
”
known as Dead Men ’s Fingers ” (Alcyonium digitatum) , while on the surrounding grounds only a fewSpecimens are to be met with . The reason of this isclear . These Spots where Alcyonium flourishes arebeds of dead Shells, mostly scallops and Spiny cockles ,which afford a foothold for the swimming larva of theAlcyonarian when seeking a place on which to settledown . Incidentally, the local range of at least threeother Species is marked out at the sam e time ; twoNudibranchs which feed on Alcyon ium are always tobe found in the neighbourhood of these Shell beds ,and also a small Isopod Crustacean which lives on thesame species .
In the case of organisms which are free to move about,the reasons for one kind of ground being more suitablethan another are not so evident . The Norway lobster,or Dublin Bay prawn (Nephrops n orvegicus) , whichabounds on the mud covering the bottom of a greatpart of the Irish Sea , rarely ventures on to the adj acentsandy grounds ; while the masked crab (Corystes) ,which frequents a clean sandy bottom , is never foundon Ithe mud . The circular crab (Atelecyclus) is notfound on either sand or mud , but Should be looked for
262 ANIMALS OF THE SEA FLOOR
origin unknown, it could be said without hesitation tobe an inhabitant of the abyss .
The physical conditions prevailing over the bottomof the deep sea are almost uniform , SO far as we canperceive , through long periods of time and throughoutall oceans . The darkness is absolute , or broken onlyby gleams of light from phosphorescent animals .The temperature is very low, at most 3
° or 4° F . above
freezing , and constant . The pressure is enormous,upwards of 3 tons per square inch at a depth offathoms . I t is hardly necessary to point out that ,once the tissues of an organism were adj usted to meetthis pressure , it would be felt no more than is thepressure of the atmosphere by the inhabitants of theearth ’ s surface . The effect of this pressure , combinedwith the low temperature
,on the metabolism of the
animal (the chemical changes connected with its vitalprocesses) must , however , be Very great . The waterabove the bottom is still or in very slow movement(un less , perhaps , in some narrow strai ts) , and is notrendered turbid by any river sediment or by m ud
stirred up by currents from the bottom . The bottomitself is covered with a fi ne ooze , usually withoutrocks or other solid bodies to afford support to sedentary organisms . In the absence of any vegetablegrowth the inhabitants of the deep sea must be carn ivorous , and as it is not possible for them to sustainlife by feeding mutually on each other , we must lookfor some external source of supply . This is to befound in the constant rain of dead organisms whichhave lived and perished in the upper layers of theocean . The existence of this constant supply oforganic matter is illustrated by the fact that theoozes which cover the ocean bed over a large part ofits extent (Chapter are formed from the Shells
DEEP- SEA FAUNA 263
or Skeletons of the microscopic Radiolarians , Foram inifera, or D iatoms , which swarm in the watersabove . This does not mean that the whole of thefood supply consists of microscopic matter , for in theupper waters representatives of almost every order ofmarine animals , from whales downwards , may befound .
In the early days of deep - sea exploration it wasbelieved by many naturalists that the unknown depthsof the ocean would be found to harbour survivors ofan earlier geological epoch which would fill gaps inthe known pedigree o f the Animal Kingdom . Thisexpectation has not , save in a few instances , beenreal ized , for , although an immense number of deepSea species have been discovered , they are ,
on thewhole
,either very like those from Shallow water or
else have been Specially modified to adapt them tothe changed conditions of life . On account of thi sgeneral resemblance of the abysmal fauna to theanimals inhabiting Shallow water at the present time
,
rather than to those of a remote geological period,
it is generally believed that the inhabitants of thedeep sea have migrated thither at some comparativelyrecent geological age , the migration probably beginningat the close of the Mesozoic Period , and continuing tothe present day .
I t is hard to point out any features in which , as awhole , the animals of the deep sea differ from those ofmore Shallow waters . Their colours are
,as a rule
,
peculiar . Fishes are usually black ,while Crustacea
are mostly red or pink . The E chinoderms Show agreat range of colour , from yellow through orange andred to crimson and purple . Uniform colours are therule , rather than blotches or stripes , such as are oftenfound in Shallow water . These markings may perhaps
. 264 ANIMALS OF THE SEA FLOOR
be regarded as protective or warning colouring , whichwould be no advantage to an animal living in utterdarkness . Many of the animals themselves are blind ,
and probably burrow in the soft ooze , or live a sedentarylife , clinging to hydroids , false corals , or Sponges .
Others have large eyes especially adapted—at least ,in some cases—for the perception of faint gleams oflight . These are probably more active and predatorytypes , guided to their prey by its own luminosity , orsometimes having themselves luminous organs
,which
serve as veritable searchlights .
While the deep- sea fauna, as a whole , is by nomeans of a primitive type , there are a few cases whereit does seem that animals of an antique type havefound in the deep sea a refuge from the more strenuouscompetition of the thickly inhabited Shallow waters .
This is notably the case with some Crustacea . TheEryon idae (Fig . a family of flattened lobster- likeanimals
,are the living representatives of a group of
which the remains are abundant in the rocks o f theTriassic and Jurassic Epochs the Hom olodrom iidae ofthe deep sea appear to be the most primitive of theexisting crabs , and resemble some found fossil inSecondary Rocks ; and certain deep- Sea prawns (belonging to the families Penaeidae and Acanthephyridae)are probably of more ancient types than their relativesin Shallow water .
Finally , the extreme imperfection of our knowledgeof the fauna of the sea bottom in nearly all regions ofthe world cannot be too strongly emphasized . Evenin Shallow waters the smaller animals are almostunknown
,except in parts of the North Atlantic and
Mediterranean and those who have the opportunityof dredging in depths exceeding 100 fathoms in anypart of the world m ay be assured that any animals
CHAPTER VI I I
YACHT EQUIPMENTB Y S . W . KEMP AND THE ED ITOR
PRACTICALLY all oceanographic work , except heavydredging and trawling at great depths , can be donefrom a sailing yacht , i f furnished with a little steamcapstan , such as is fitted to sailing trawlers , and costsabout £100.
In a sailing yacht without any steam whatever thecollection of water samples , Plankton work down toat least 500 fathoms , and dredging and trawling inShallow water can be carried on without difficulty .
But in a sailing yacht , whether with or withouta capstan , the rig , tonnage , freeboard , and deck spaceare SO important that it would be well to inquirebeforehand from experts what branches of the workcould be most suitably pursued .
With steam available for propulsion as well ashauling , oceanic work will be done more easily , and
more can be got through in the same time . I t is notonly true that no time is wasted in tacking betweenstations , but the handling of the Ship when at workis much facilitated . In using most deep- sea instru
ments , especially if driven by messengers (weightswhich Slide down the rope) , it is most important thatthe rope should be kept vertically up and down , and
not al lowed to stream away as the Ship drifts .
With plenty o f steam on board , the capstan can be266
STEAM HAULAGE 267
replaced by a steam winch or Windlass , with the resultthat work can be carried on at far greater depths ,and far more rapidly and safely .
F IG . 1 9 2 .-STEAM CAP STAN FOR USE WITH SA ILINGYACHTs z SU ITABLE
FOR THE LARGEST TRAWLS . (B Y PERM I SSION OF MESSR S .B ROOKE AND CO . )
Supposing that there is no deck engine already onboard
,the owner will find that a good winch can be
utilized for practically every kind of work—ther
268 YACHT EQU IPMENTm om eters , water-bottles , soundings , tow nets , dredges ,and trawls , as well as for hoisting boats and anchor ,cargo and coaling work . With winches (as withmuch other gear) , the owner , master , and engineermust settle the exact specification , according to thework to be done . We can only give the most generalindications as a guide .
One may use (1 ) either a regular trawlingwinch ,
on the barrels of which the rope is stored ; (2) or a
cargo winch , which will haul the rope but not storeit . Of these two types , there is no doubt that theregular trawling winch is much to be preferred . Itwill not only serve for the ordinary work of a cargowinch , but when scientific work is required it will savedeck Space and hands .
We figure a commercial trawling winch , Showingthe usual two hauling and storing barrels in the centreof the engine . For really deep-water work this typerequires some modification . In the first place , ifrequired for trawling and dredging only , a Single largebarrel is better than two smaller barrels , the divisionsbetween the latter having been known to burst andcut the rope under pressure . In the second place thebrake wheels should be cast solid with the barrel ends ,and strengthened by radiating ribs , in order to resistthe enormous lateral thrust of a great length of ropewound under tension . But if it is proposed to useclosing tow nets and other . apparatus with small‘
messengers,which require a Slighter rope (p . in '
addition to trawl and dredge , it might be well toretain the double barrel , using one barrel for eachrope , and strengthening the division between them .
In this case the barrels Should be clutched separately ,
which is not always the case with commercial trawlingwinches .
270 YACHT EQUIPMENTThe following specifications of stock commercial
W inches have been supplied by the courtesy of a wellknown firm
App roximateCylinders . L ifting
Power .
A pproxima te
Price
{ ODS
Trawling win ch 6 by 1 25 10
Cargo win ch 5 10
But the capacity can be varied to any workable extent .
The largest stock pattern by these particular makerswould carry fathoms
, and the smallest only200 fathoms of 1 15- inch rope .
A cargo winch can be used for all deep-water workif it carries a largish , deeply grooved drum for winding ,of (say ) 1 8 or 24 inches diameter , in addition to theordinary small barrels . This drum will only carrytwo or three turns , and the wire must be taken up , as
i t comes off the drum,on to a storage reel o f some
kind . It is no small labour to reel up fathomsor SO o f wire rope by hand power , and as a
‘
rule itcannot be taken up as fast as the winch can deliver itthe method is therefore wasteful o f both time andlabour , and the storage reel Should , i f possible , bedriven mechanically . I f a fairly powerful cargo winchis already on board
,which it is not desired to displace ,
we should recommend that a one or two horsei powersteam engine Should be fixed behind the winch , so
that it could drive,directly or by chain gear , which
ever storage reel was required at the moment . A
recent expedition used an electric motor for this work .
Another plan which has been suggested is to drive thestorage reel by an endless rope from the small barrel
DEEP- SEA WORK 27 1
of the winch,the rOpe being kept taut by passing
through a block against which a weight pulls . Whenthe reel tends to run too fast , the rope-drive will Slipand so provide the necessary compensation .
It Should be remembered that with a cargo winchthere is much more wear on the warp than with thetrawling winch . In using either of the above methodscare should be taken to reduce the Slip on the drivingdrum to a minimum .
Storage reels for the above purposes Should be ofextra solid construction and provided with a powerfulhand brake . Most of the patterns on the market areonly intended for occasional use
,and are consequently
of the very lightest build , with inferior bearings .
A .—Deep Sea.
1 . DREDGING AND TRAWLING .
AS this is the heaviest and in many respects the mostdifficult part of oceanic work , i t Should be the first tobe considered .
Next in importance to the winch is the wire rope tobe employed this must be flexible
,lest it kink and
snap when the strain is taken off, as , for example ,
when the trawl touches bottom . Flexibility impliesseveral strands
,each of numerous wires
,and this
unfortunately involves weight . Fig . 1 94 Shows asection of a suitable rope , and displays Six strands oftwenty- four wires each (6 x 24) ; each strand has ahemp core , and the whole rope a hemp heart .
Before selecting a rope , i t is of great importance toselect
'
a manufacturer with care it is not every firmwhich understands the special demands made upon arOpe by deep- sea trawling .
272 YACHT EQUIPMENTFrom the catalogues and samples of two reliable
makers we take the following specifications as a guide
We ight p erWires . Circumference .
100 Fathoms .
inches.
The selection of a rope will,of course
,depend largely
upon the depth to which it is proposed to work,the
probable character of the bottom , and the Size of thedredge or trawl . If it is proposed to work down tobut not over fathoms , a Single length of
fathoms of 1 - inch rope,with breaking- strain
about 3 tons , * would probably serve the turn . Takingthe second rope specified as an example , a factor ofsafety of four allows 4 hundredweight for the trawl andits contents .
3
Work at anything over fathoms implies an
It m ay be m entioned here thatH .M .S . Chal lenger , used
hem p ropes - of 2 in ches and 2% in ches c ircum feren ce , withbreaking- strain s of 1 ton 1 2 hundredweight and 2 ton s 6 hun
dredweight respectively . For shallow-water work was em
p loyed a rop e of 3 in ches c ircum feren ce ,with breaking-strain
of 2 ton s 1 1 hundredwe ight . B ut it m u st be rem embered thatin water a hem p rope carr ies m uch m ore of its own we ightthan a steel rope . Sir John Murray in form s us that the rop e
was hau led at the rate of fathom s p er hour ,and that
dur ing the three and a half years ’ cru ise , when trawlings and
dredgings were m ade at 3 5 4 station s ,there were on ly eleven
cases of parting of the rope . Wire ropes were first used for
such work by Agassiz in 1 877 .
274 YACHT EQUIPMENTable tension , the spreading is best done by means of amechanical Spreader this apparatus is sometimessupplied by the manufacturers of trawling-winches . Insome patterns the wire is Spread by a long steel fork ,
which moves, either mechanically or by means of ahandle fitted to a long pivoted arm
,across the face
of the barrel . In this type the friction on the warpwhen hauling heavy weights would be very destructivea carrier holding three rollers (two upright and one ’horizontal) should be substituted . In a simple type
,
which one of us is able to recommend,the carrier and
rollers are made to travel on a slide by the rotation ofa long screw-Shaft , actuated by a handle from oneSide . The work can be done with more labour byusing a snatchblock on a lanyard or Spar ; but whilethis m ethod will be found efficient for light work , orfor reeling wire that is not under tension , it is scarcelyapplicable when haul ing heavy gear , for in such casesthe strain is so great that the united efforts of twomen and a purchase will be required .
Greasing is also an essential to the preservation ofwire rOpe . AS it comes in , it Should pass through welloiled cotton-waste . Castor oil is excellent , but expensive boiled oils seem to form a good hard coat theordinary fluid machine oils seem to disappear at once ,and should be renewed daily if used at all .I t should be stipulated with the makers that all
wire ropes be sent properly coiled on a reel of somekind . As soon as received, if the rope is to go on thetrawling-winch, it Should be paid on to the winchbarrel under a steady strain with the reel revolvingunder no circumstances should it be paid on with thereel flat , or from a coil . Before being used for trawling ,
the whole length should be run out at sea , and carefullyreeled up under a fairly high strain .
ACCUMULATORS 275
Two other pieces of gear are advisable—an accumu
lator and a recording sheave . The old type of accum u
lator consisted of a number of stout cylindrical rubberstraps between two boards , the whole slung from aderrick or Spar , and carrying the block over which thetrawl rope runs out-board ; the obj ect of this was tolessen any sudden strain on the rope due to the trawlhitching , and to warn the man in charge of such strain .
Since the invention of pneumatic tyres , it has been sodifficult to get reasonably pure rubber that the lessbulky and more reliable steel Spring accumulatorsseem to be advisable . If trawling from a derrick , thetopping lift , passing over a block stropped to the mast ,is brought down and made fast to the head of a longsteel Spring , rigged up against the mast .
* A suddenstrain on the rope pulls down the derrick head
,the
Spring yielding . Such an indication will often enablethe gear to be recovered before it is seriously damaged
,
while with very severe pitches the warp is (probably)saved from snapping .
For really heavy trawling a nipper may be substi
tuted for the accumulator , or used in conjunction with it .
This (Fig . 1 95 ) is attached bymeans of a hemp rope to thewinch or some other solid deck fixture , and the Slacktripping line is also shackled to the same support theaccompanying figure will explain the method employed . Any undue strain causes the hemp rope tobreak
,allowing the wire to pay out from the drum or
reel (if the brake is left open) , while the nipper ischecked by the tripping line , and either falls to thedeck or all ows the wire to render through it , accordingto the particular make fitted . A small nipper will also
This arrangement is figured in Report of the Siboga
Expedition , Descrip tion of the Ship , by Lieutenant G . F .
Tydem an ,Plate I .
“
276 YACHT EQUIPMENTbe found useful for holding the warp in the event ofanything going wrong Figs . 1 96, 1 97 illustrate a Simpleform which m ay be employed for this purpose .
LockingPlateS inch Sta
l'
fi Inch wnre war
F IG . 1 9 5 .—N IPPER FOR HEAVY TRAWL ING
.
FIG . 1 96 .-SMALL N IPPER FIG . 1 9 7 .
—SMALL\
N IPPER
R ENDER ING . GR IPP ING .(FIGS . 1 9 5 To 1 9 7 BY PERMISS ION OF MESSRS . B ULLIVANT . )A recording sheave (Odometer) of some kind is n eces
sary for work in deep water . This need only consistof a strong sheave of known circumference (1 Or f
278 YACHT EQUIPMENTwire diameter
, 51
3 inch breaking- stram‘
, 280poundsprice 23 s . per 300 fathoms .One of the present writers , after two years ’ eXperi
ence , is able to Speak highly of the following strandedwire of German manufacture : 3 x 7 galvanized steelwires of 0-
4 millimetre gauge ; diameter , 353—2 inches ;
breaking- strain , pounds ; price £6 75 . 6d . per
fathoms .
The high breaking—strain allows this wire to beused for physical operations with water—bottles and
capsizing thermometers .
The various types of deep- sea Sounding machineshave each their own supporters . By the courtesy ofthe manufacturers we are able to give here the followingprices of the Lucas machines as a guide (1 ) For depthsto fathoms coupled to a Brotherhood threecylinder engine the whole fitted to an iron base , £1 3 1(2) the same , with rope-wheel for driving from deckengine
, £52 . The capacity is calculated for piano-wireof 22 gauge .
For really deep - sea sounding it is advisable touse a heavy Sinker of 50 pounds , which is detachedon striking bottom and left there this method enablesthe wire to be hauled rapidly, and without dangereither of breaking the wire or of bursting the barrelon which it is reeled up . The sinkers are made ofcast- iron .
Several types of deep-sea sounding leads are in use ,their form being dictated by the fitting employed tobring up a sample of the bottom (cf . Chapter VI . ,
The Sea For the latter purpose have beenemployed a cup (not. now in use) a heavy tube , which ,
when being hauled,is closed below, either by a butter
fly valve or a cock ; and a snapper , consisting of twotightly fitting buckets which grip a bottom sample .
LIGHT ROPE 279
The second of these is represented in Fig . 1 57 , p . 202 ,
the third in Fig . 1 99 .
A full account of the Le Blanc sounding machine isfurnished in Lieutenant Tydem an
’
s Siboga Reportalready quoted . The Sigsbee machine is described inthe Bulletin of the United States Fish Commissionfor p . 3 1 2 .
The wire should be well greased . A mixture ofcastor oil and tallow is recommended for stranded wire ,applied hot . For single—strand wire boiled oil is good .
Very great care should be exercised in spreading thesounding wire evenly on the barrel , and the same precautions taken in paying it on to the barrel from themanufacturer ’s reel , as in the case of wire rope .
3 . OTHER WORK .
I t is not economical , either of time , labour , or thelife of a rope , to use a heavy rope where a l ighter onewould do the work, and a 1 - inch rope is not welladapted for other uses than trawling , dredging , and bigvertical nets . A lighter and cheaper type of rope canbe used for reversing thermometers , current meters ,water-bottles , Open and closing tow nets—in fact , foreverything except bottom work .
* A rope of this typewas spun to the order of one of the present writers formid-water work down to 2 ,500 fathoms ; it consistedof seven wires of 16 gauge plough- steel ; diameter ,
53
5 inch ; breaking - strain, 2 tons ; weight (in air)42 pounds per 100 fathoms ; price about z rs . per100 fathoms . I t Should be stipulated with the makersthat a rope of this type be Spun from continuous
It is n ot recomm ended to use Six therm om eters with anyrop e of so large diam eter ; the vibration tends to jar the irindices down , and
_thus to give defective readings
°
286 YACHT EQUIPMENTlengths of wire , with no brazed j oins ; the latter areap t to give way under a severe tension ,
and to catchand strand when running thr ough a fair lead . I t ispossible that so stiff a rope would kink if used forbottom work .
B .- Shallow Water.
The hints already given relate to the most difficultand troublesome part of all oceanographic work
,that
which involves the most power,t ime
,weight
,storage
space , skill , care , and expen se . I f deep- sea work is themost ambitious , it is also the most interesting if it isthe most difficult
,it is also the most needed
,and the
most productive of striking results .
On the other hand ,excellent and valuable work can
be done at small depths in almost any part of theworld . Even in home waters little has been donesystematically outside the 100- fathom line ; beyondhome waters (except in one or two favourite areas)anyone with a rowing-boat and a little apparatus canadd materially to knowledge .
1 . DREDGING AND TRAWLING .
In shallow water,down to (say ) 200 fathoms near
land ,it must be remembered that if the net catch on
rocky bottom, a breeze acting on the freeboard of a
large yacht or steamer will impose a very great strainon the rope ; a trawl full of stones or mud is also amenacing possibility . For such work a I i—inch or 1&inch rope
,with a breaking- strain of 4 to 8 tons, is
desirable the lifting power of the deck engine can besomewhat reduced ,
but an accumulator or somesimilar protection is certainly required , and a recordingsheave indispensable . With this gear a yacht can
°
282 YACHT EQUIPMENTThe reel or sounder can be fixed close to the Ship ’s
rail , or if fixed amidships the wire can be led over therecording sheave slung from a davit or from a spar ,
1 9 8 .-LUCAS SOUND ING MACH INE , HAND -D R IVEN . (FROM
K RUMMEL’
S HAND BUCH DER OZEANOGRAPH IE , ” BY PERM I SS ION OF J . ENGELHORN’
S VERLAG,STUTTGART .)
F IG . 1 9 9 .—SOUND ING-LEAD S , WITH SNAPPER FOR COLLECTING A
B OTTOM SAMPLE . (LUCAS SNAPPERS . )The lower lead has a weight which is detached on striking thebottom .
which can be swung inboard when the gear is up , inorder to enable the instruments to be convenientlyattached and detached .
Lighting.
—If there is a dynamo on board , a cargocluster , with enam elled iron shade and flexible con
LABORATORY 283
n ection , is very useful for working at night . Heavynets should never be shot at night un til the wholecrew is thoroughly well practised in the use of thegear a man can easily lose his life by getting a turnof the warp or spans round his leg . A portableelectric torch ” i s very useful for reading the log ,etc at night .
C.—Laboratory Fitting.
Some sort of place will have to be used as a laboratory , where the scientific log can be written , collectionspreserved , labelled , and packed , etc . so that a fewnotes may be here added on fitting it up as a laboratory .
It is perfectly possible , by a little forethought , todo solid work , and yet to keep the yacht as spick andspan as any owner can desire .
The position Of the laboratory and its fittings willdepend entirely on the rig and build of the vessel . Itshould be amidships and on deck , if possible . I t cannothave too much light . A poop deck-house
‘
m akes anexcellent laboratory . Linoleum is the best of floorings .
A very important matter is the work table this canbe either fixed or swinging , and both have their supporters . A stout table , of the kitchen type , with awell oiled top , and a large drawer for charts and flatpapers , and firmly bolted down , has this advantage overthe swinging pattern—that the space below can be fittedup with pigeonholes of various Sizes to take appar atusand accessories of all kinds . As a great deal of thework must be done standing , a height of 3 feet 6 inches*
is less back-breaking than the ordinary table height .Half at least of the surface Should be divided uppermanently
,by fiddles about 3 inches high , into
The taller of the two wr iters prefers 2 feet 10 inches 1
284 YACHT EQUIPMENTcompartments suitable for the bottles or other apparatus required . If this is the only table in the laboratory, the other half should be left clear for writing ,charting , drawing , etc but a separate table , at whichone can sit for writing and for a microscope
,is a great
boon .
If a swinging table be preferred , a stout rail , levelwith the table and about 1 3 inches clear of its edge ,fixed at the corners to stan cheon s from the floor , willbring up any one lurching against it in a heavy Sea .
I f there is a dynamo on board , a cluster of lampsshould be over the centre of the table but a hangingOil lamp should not be arranged to throw a Shadowover the writing table .
The particular work which it is proposed to attemptwill
,of course
,determine the character of the bottles
and apparatus to be kept in the laboratory ; butsweetmeat jars , corked store bottles large and smal l ,and corked tubes , are needed in all kinds of zoologicaland botanical work , and Should be racked in quantitiesround the walls . Bottles of killing and preservingfluids Should be racked together . A 2 -gallon milkcan , with tap below , and a filter of fine boulting- clothat the top ,
is handy for the necessary store of cleanwater , whether salt or fresh (Ship ’ s fresh water notbeing ideally clean) ; it should be emptied and re
filled every day . An enamelled Slop- pail , with a top ,
should also be racked in a handy position to receivemess and waste fluids of all sorts .
1 . Plankton —Special receptacles in the fiddles ofthe work table should be made to take two or threesweetmeat j ars or large square j ars , into which thecontents of the tow net tin are emptied for sorting .
Other compartments should take those smaller bottlesin which the larger organisms are to be pickled . Empty
‘
286 YACHT EQUIPMENTnumbers of indeterminable forms will be found thesemay be entered as Gadoid A , Asteroid A ,
etc . Thesame Species occurring in subsequent hauls Should bereferred to in the same way , but unless the identityof the two forms is certain a sample must again bepreserved .
When possible the stomachs of fish Should be examined, for, apar t from the light which is thus thrownon the food- supply of the species, they occasionallycontain invertebrates which are seldom or never foundin any other way .
Search should be made for hermit crabs and wormsresident in the dead shells of molluscs , and for en
crusting animals living on stones or other débris . As a
rule i t is best to avoid attempts at extraction or removal .The comparatively large animals , obtained in bags
of sprat meshing , m ay be dealt with in the same way ,
but the sorting of the material collected by the finemeshed nets usually demands so much time that immediate treatment is out of the question . In such casesi t is best to transfer the whole to a j ar containing 5 percent . formalin or formol-alcohol , until a more favourable occasion arises . It should be remembered thatformalin , even in a 5 per cent . solution , is sufficientlyacid to act as a decalcifying agent all animals whichare liable to inj ury from this cause should be transferred as soon as possible to 70 or 75 per cent . alcohol .The sand , mud , or ooze , which is sometimes brought
Up in considerable quantity by the trawl or dredge ,generally contains a considerable number of animals .
For the treatment of this material sieves must beemployed ; the p rocess is rather laborious, but theresults are as a rule eminently satisfactory . I t isbest to obtain a set of four sieves (with different sizedmeshes) , which may be employed successively , using the
STORAGE OF SPECIMENS 287
coarsest first . The sieves should be made of brass wiregauze , and are more convenient if fitted with handles
(Fig . The coarsest should have meshes about
i inch square , the finer patterns with eight , Sixteen , andthirty- two meshes to the inch . I t is advisable to preserve a sample of the ooze in alcohol , for many minuteorganisms will pass through even the smallest of theabove meshes . A stream of water from a servicepipe may be turned into the sieve , or it may be dippedrepeatedly in a bucket of water . Shaking is verydestructive and Should be avoided .
Samples of stones , sand , mud , or ooze Should alwaysbe preserved ; small canvas bags are useful for thispurpose .
3 . For chemical and physical work little can bedone at sea
,beyond the collection of water samples ,
without extremely elaborate appliances . The fittingup of a laboratory for immediate analysis is a mattertoo technical for an elementary work such as thepresent, but the Society is prepared to advise on thepoint . I f such analysis is not contemplated , thechemical and physical work demands little more thanproper storage for bottles and apparatus , and awriting- table .
4 . Storage of Specimens at Sea—The larger androugher specimens Obtained by dredge or trawl, afterthe necessary preservation (Chapter XI .) should havetheir label tied on to them , and then be wrapped incheese- cloth and stored in spirit or formal in . It ishandy to have on deck for this purpose a woodentank , lined with lead (zinc tends to pit with formalin) .The lid should fit on to a thick rubber flange
,and be
held down by wedges driven under the cross- stays ofthe tank . Trays of lath inside serve to distributethe pressure of the upper layers of specimens . A
. 288 YACHT EQUIPMENTuseful Size of tank is 3 x 1§x 1§ feet high . On a
long cruise the contents of this can be occasionallytransferred to barrels and
,headed up ; to be sent home
or stored in the hold .
Large but more delicate specimens can be stored intobacco j ars with very wide mouths these are madein various Sizes , and the lid is screwed down tightlyon to a rubber flange by an iron clamp and thumbscrew . Two 4-gallon j ars of this type , racked in apadded box , Since they are brittle , will hold a very largequantity of material .Sweetmeat j ars , with a cork ring , and the numerous
forms of screw- topped j ar on the market , are not tobe recommended for prolonged storage where theycannot be constantly examined , least of all in thetropics , unless packed in barrels or metal tanks , ortied Over with bladder .
Stout sample-bottles of various sizes (4 , 8 , and1 2 ounces , are useful) and stout unshouldered tubesof various lengths with carefully picked and fittedcorks (not bungs or Shives) , will carry the smallerstuff . Fill all tubes and bottles with fluid upto the very cork . Put on the galley- range a goodsized glue-pot
,containing paraffin wax (melting-point
100° F but harder if for use in the tropics) with a
little white beeswax ,and dip necks and corks twice
in this to make all tight . These sample bottles arebest stored in trays
,partitioned by corrugated straw
boards ; but , for reasons of great weight , too manytrays should not be stored in one case . Longtubesare best in a racked box . Sawdust packing is messy ;it sticks to wet fingers
,and is transferred unpleasantly
to the specimens .
. 296 DREDGING AND TRAWLING100 fathoms patterns from 3 feet to 3 feet 6 inches longand 8 to 9 inches broad are useful , while for very greatdepths large heavy makes up to 5 feet long and 1 footbroad are recommended .
The term naturalist’s dredge m ay be restricted to aform of frame which differs from the foregoing onlyin the absence of swords . The effect of this is that thestraight edge of the frame tends to skim the surfaceof the ground instead of biting into it . This type hasbeen almost entirely superseded by that mentionedabove .
The conical dredge is designed to dig into the soil ofthis it brings up a good sample , together with specimensof burrowing animals .
The bag or net which is fastened to the dredge shouldbe quite as long as
, if not longer than ,the frame
, and
should not be tapered behind . I t may be made oi
strong manila trawl- twine of 2 - inch mesh,
* but a mostsui table bag m ay be constructed from the cod end of anold trawl ; this is usually easily procured and fitted .
Loose chafing pieces attached to the outside are veryuseful , and save a great deal of wear and tear . Forcatching small animals and for use on smooth ground ,
a lining of sprat netting of 1 - inch mesh , or even finer,may be fitted inside the bag (some firms stock an extrastout make of sprat netting, which is excellent for thispurpose) . The lining should be made fully as large asthe outer bag
, so that the strain is taken up by thelatter .Two small bags may also be fitted in the tail end of
the lining one of these is made of Shrimp netting , andis designed to catch some of the smaller organismswhich would pass through the r - inch mesh , while the
Meshes are m easured d iagon ally when the n et is stretched
out thus 2 - in ch m esh m ean s op en ings of 1 square in ch .
THE DREDGE 291
other is made of sacking or stout canvas , and preservesa sample of the sand or other fine bottom material .The two main bags—oi trawl- twine and Sprat
netting—are lashed to rings at the back of the dredge ,or they may be fastened directly to the frame by meansof
'
seizing wire . Each bag is opened or closed behindby means of a running string through the meshes .
The small bags are stitched in position through boththe main bags , and their ends are secured by a lashing .
The nets for small frames for use in shallow waterare generally of a simple p attern . For these a piece ofthe cod end of a Shrimp- trawl or the extra stout Spratnetting mentioned above is suitable , with or withouta lining of mosquito netting .
For the conical dredge a strong canvas bag is recommended . Dredges used in deep water should alwayshave a piece of chain fastened to the end of the bag toprevent it getting foul of the frame while being loweredto the bottom , and this device is also useful at all depthswhen the net is new .
A tow net made of cheese - cloth , wi th a strong canering , is sometimes fastened to the dredge . I t is usuallyattached to the shackle at the end of the warp , with astrop sufficiently long to allow it to lie with its moutha little behind the frame . By this arrangement thetow net is designed to catch the small animals disturbed by the swords of the dredge . This method hasbeen known to produce the most satisfactory results
,
but the safe recovery of the tow net is decidedlyuncertain .
Tangles (or swabs) consist of lengths of hemp ropeteased out , and fastened to the end of the bag or toan iron rod attached by chains to the frame . Starfishand other animals become entangled in the threads ofthe hemp , and are thus drawn to the surface . Tangles
292 DREDGING AND TRAWLINGwere very highly Spoken of by the naturalists on theChallenger , but in recent years they have not beenmuch employed .
The dredge should be attached to the warp in thefollowing way The eye at the end of one of the bridlesis secured to the eye at the end of the warp by means ofa screw shackle , and the other eye is made fast merelyby a strong strop or lashing of trawl- twine . Thisarrangement is invaluable in the event of the dredgebecoming fast among rocks , for in that case the lashingparts and the frame is drawn along sideways
,thus
usually clearing the Obstruction and preserving thedredge from inj ury .
In 50 fathoms of water or less it is usually best to
p ay out warp to the extent of two or thr ee times thedepth ; in deeper water less is required , and whenworking in soundings of fathoms or more
, 400 or
500 fathoms in excess of the depth will be foundsufficient . In many local ities , however , the nature o fthe bottom is so extremely rough that , if this amountof warp i s given , the strop parts on every occasion .
On such grounds it is advisable to pay out only a littlewarp in excess of the depth; and , after the ship has beenstopped
,to ascertain if the dredge is biting by holding
the warp .
* More warp may then be given cautiouslyif required .
Shooting and Towing.
SailingYachts.
—Always tow with the tide if possible .
With a moderate amount of way on the boat thr ow thedredge over on the windward quarter , and pay out asufficient length of warp . Make the warp fast witha stop of small rope , but be sure to have the end well
B y holding the warp it is Often p ossible to feel a heavydr edge working,
even at dep ths of 500 fathom s .
294 DREDGING AND TRAWLINGthe ship m ay at once be brought up on her course whenthe gear is clear away .
When a sufficient length has been paid out,the warp
is made fast by means of a rope- strop and rollinghitch if the dredge fouls , this strop should break .
When using manila a few turns of the slack warpshould be taken round the bollards
,and when towing
from the winch barrel the brakes should be left openif plenty of wire remains .
Tow dead slow, preferably with the tide , feeling thewarp from time to time to make sure that the dredge isbiting properly .
I f the dredge hitches and the strop parts,stop the
ship at once , and if it does not clear itself immediatelyhaul it up . Should it still remain fast , lead the warpforward and go astern , steaming slowly over the dredge .
The dredge is usually left on the bottom for fromten to thirty minutes if longer time is given the netmay fill right up and the strop on the bridle may part ,involving the loss of the greater part of the contents .
The procedure in hauling is obvious . The Ship isstopped , the rolling hitch is cast off , and the warphauled by hand
,capstan
,or winch . In the latter case
it is well to see that the warp is evenly spread acrossthe breadth of the barrel otherwise loose bights appearwhich later on will cause considerable annoyance .
With a considerable amount of warp out , it is allowable to go slowly and cautiously astern at the comm en cem en t of hauling , a careful watch , o f course ,being kept that the warp does not come foul of thepropeller . If block and tackle are employed for getting
It is som etim es d ifficu lt to m ake a rolling hitch ho ld on
well-o iled wire -warp , esp ec ially when of sm all d iam eter ; in
su ch c ases it wil l be found that a serving of trawl-twin e or a
can vas p arcell ing will m aterially assist .
THE BEAM TRAWL ’
the dredge inboard , i t is advisable to keep the frameslung up
,and if necessary lashed ,
until the contentsof the bag have been emptied .
Trawling.
Trawling is the best and easiest way of obtainingextensive samples of the bottom fauna
,but the method
can only be satisfactorily employed on smooth ground .
Three types of trawl are available for biologicalinvestigation—the beam tra ,
Agassiz trawl , andotter trawl .The Beam Traw1. —In this pattern the net is kept
open horizontally by a long beam of greenheart oroak , and vertically by a pair of iron runners or heads ,Fig . 202 gives a good idea of the appearance of theframe .
Beam trawls may be used at practically any depth ,
but in very deep water they Show a tendency to capsize .
the beam dragging along the bottom,and the foot rope
completely closing the net . In such cases the haul isnaturally a complete failure . With a certain amountof experience in shooting this difficulty may be largelyovercome ; but the otter and Agassiz trawls will befound more efficient for work in greater depths than300 fathoms .
The beam trawl collects a larger number of invertebrates than the otter trawl , but does not secure so
many fish—active species of the latter are doubtlessscared by the beam in its passage along the bottomTrawls of this pattern range from 6 to 50 feet In
beam- length . Small makes, with a 6 or 8 feet beam ,
are easily handled from a rowing boat or launch .
The commercial beam trawl is usually from 40 to
50 feet in length ; these sizes are , however , unwieldy ,
DREDGING AND TRAWLINGand the procedure in shooting and hauling is verycomplicated . Yachtsmen will find patterns with a1 5 to 30 feet beam am ply large enough . In theseSizes the Shooting and hauling does not present anyconsiderable diffi culty .
F IG . 200.—B ALL D RED GE . F IG . 2O I .
-AGA S S Iz TRAWL(AFTER WYVILLE THOMSON . ) B LAKE PATTERN .
The beam trawl is towed by a pair of spans whichare shackled to eyes in the front of the heads . Eachspan should be three and a hal f or four times the lengthof the beam , and as stout as the warp . The head ropeof the net is as long as the beam ,
and is laced to it .
298 DREDGING AND TRAWLING'
As it is intended to scour the bottom,it is necessary
to make the foot rope heavy for medium- sizedtrawls 8- inch rope is recommended
,weighted by the
attachment of lengths of chain .
The net Should be about one and a half times thelength of the beam . It is made of hemp or manilatwine of 2 to 25 inch mesh in the back and belly ,
and 1 inch double mesh in the cod end . The lowerpart of the cod end , which comes in contact with theground , is protected from chafe by an extra piece ofstout netting attached on the outside .
The trawl moves comparatively Slowly over the seabottom , and consequently fish which have entered thenet frequently manage to swim out again and avoidcapture . To obviate this , pockets are formed bystitching together the back and belly of the net at thesides
,as indicated in Fig . 202 . The net is Opened and
closed behind by a running string through the meshes .
The 2 or 25 inch mesh is much too large to retainany small organisms . The whole net m ay be linedwith sprat netting (r - inch mesh) or bags of the samematerial and of mosquito netting may be attached to theback
,in the path of the swirl caused by the foot rope .
The latter system has the advantage that the coarserpart of the catch is kept in the trawl , while samplesof the smaller animals are separately collected andsaved from crushing .
Tow nets with cane or iron rings and a long cheesecloth bagmay also be attached to the beam or to thenet . If placed too far back , they frequently fill withsand or mud ,
and burst .
The very small makes of trawl , which are suited foruse from rowing boats or launches , are usually knownas Shrimp trawls . In these the net is made o f stoutsprat meshing with a lining of mosquito net .
SHOOTING THE TRAWL 299
The length of warp required varies with the depth .
The following table will give some indication of whatis required
In sound ings up to 50 fathom s—3 tim es the depth .
of 50-200 25
of 200-
500—2
of over 500 —500 fathom s in excess
of the depth .
Beam trawls may be towed from the warping chockaft
,from a trawl post , or from a wide-mouthed snatch
block slung from a derrick or davit .
Shooting over the stern is much the most convenient ,but the method can only be used with very smallpatterns ; As a general rule , i t will be found best toShoot and haul from the port side as far aft as possible .
The following is an outline of the procedureThe trawl is laid on deck with the heels of the irons
close to the rail,and with the net brought back over
the beam . The spans are coiled down on deck , andthe warp , after it has been passed through the trawlport or other fairlead , is shackled to them . I t is bestto use a separate shackle for each span . When thesepreparations are complete , way may be got on theship
, and the trawl Shot with helm hard a- starboard .
The frame is lifted to the rail by hand or by tackle .
The cod end is put over the side first , followed by theheads and beam , the trawl drifting away on the portquarter as the spans uncoil . I t is best to square thetrawl by checking the after span , while the other islet run freely . This should be done while the net isstill at the surface and can be seen . When the wholelength of the spans has disappeared , the warp may be
A sn atch-block for this purp ose m ust be wide enough to
allow the p assage of the shackles c on n ecting the warp an d
Sp an s , and shou ld have a deep V- shap ed groove .
3 66 DREDGING AND TRAWLINGeased Slowly away , and the Ship brought up on
'
her
course . In'
most cases it will be necessary to tricethe warp up to the after hawse pipe , to keep it clear ofthe propellers . As has already been mentioned underDredging , it is advisable to start shooting with theship ’ s head about four points to starboard of hercourse , so that She may be straightened up directlythe gear has gone away clear . I t is necessary to keepa steady strain on the warp , and to check it repeatedlyas it is being paid out . Neglect of this precaution isthe most frequent cause of a foul shot . When a sufficientlength has been given, the warp is made fast (as indredging) by means of a rope stop or by a nipper
(p .
The trawl is generally fished for from one and ahalf to two and a half hours . By holding the warpit is possible , in moderate depths , to feel the gearworking its way along . With a little practice a usefulestimate of the nature of the bottom can be formed bythis means . If the trawl hitches and the stop parts ,the net should be hauled at once . I f it still remainsfas t , lead the warp to the bow, go astern and pull itbackwards off the obstruction .
Hauling small beam trawls is not difficult . Thewarp is reeled in until the spans appear , and eachSpan is separately hauled by hand until the beam andirons are got on board the net may then be hauledin , foot rope first . This procedure cannot be appliedto larger patterns (with beam more than 1 5 feet inlength) , for in these makes the weight is too great toadmit of the Spans being hauled by hand . The addition of a beam rope is almost essential in suchcases , and it is also advisable to step a stout davit witha snatch-block on the port quarter . The beam ropeis in reality a third Span ,
used only in hauling . I t is
302 DREDGING AND TRAWLINGconsiderably, and this m ay be conveniently done bywinding chain around the iron beams . The net shouldbe of shrimp or Sprat mesh . The Agassiztrawl is more useful for catching invertebrates thanfor fish . The procedure in Shooting and hauling doesnot differ in any essential way from that already detai ledunder Dredgi ng (pp . 292
The Otter Trawl . —For work on small steamboats,
especially where a winch or capstan of any kind isavailable , a small otter trawl is more handy to use thana beam trawl of equal Spread . The shape of the netof an otter trawl is practical ly the same as that of abeam trawl , the difference between the two trawlsconsisting in the method adopted for keeping themouth of the net open . In the case of the beam trawlthis is effected by the long wooden beam and the twoiron
'
heads . In the case of the otter trawl two oblongboards
,fitted with iron shoes—the otter boards—are
used . The mouth of the net in both beam and ottertrawl has a heavy ground rope below, which dragsalong the sea bottom ,
and a head line a bove , which inthe beam trawl is attached to the beam , but in theotter trawl is floated up in the water by means of corksor (in deep water) glass floats attached to i t . Thesetwo rOpes , the head line and the ground rope , are madefast at each end to the hinder ends of the oblong otterboards
,which
,when the net is working , stand on their
lower iron- shod edges on the sea bottom .
The two otter boards act after the m anner .,
of kiteswhich are flown ” from the stern of the ship bymeans of two towing warps
,one bearing away to star
board,the other to port . Each towing rope is fixed
to its otter board by means of iron brackets or of fourchains
,in such a way that the point of attachment is
behind the centre of the board , and the board there fore
THE OTTER TRAWL 303
moves forward obliquely to the direction of tow .
The two boards in this way keep a strain on the headline and ground rope , which increases with the Speedat which the vessel is towing . I t is probable that undernormal working conditions the distance which the boardsactually keep apart is about two - thirds the length ofthe head line of the trawl . The head line being floatedwith cork
,rises up in an arch between the two boards
,
and gives a much higher opening to the mouth of the netthan is yielded by the beam trawl , in which the heightof the opening is fixed by the height of the beam abovethe ground . This increase in the height of the Openingof the mouth of the net constitutes one of the chiefadvantages of the otter trawl as a fishing instrument
,
Since the take of round .fishes , which swim a little abovethe actual bottom
,is thereby much increased .
The size of the otter trawl usually worked on a steamtrawler is as followsLength of head line
,86 feet . Length of ground rOp e ,
1 25 feet . D imensions of otter boards length, 8 feet
height, 4 feet 3 inches thickness
, 25 inches . Sizeof mesh ,measured diagonallywith mesh taut , diminishesfrom 55 inches in the square to 22inches at cod end .
The fine -meshed nets already mentioned in connection with beam trawling m ay also be fitted to ottertrawls .
5
On a commercial steam trawler two independenttowing warps are used , one for each otter board ,
andspecial iron gallows are fixed to the vessel ’s side
,fore
and aft , for getting in the heavy boards . I t is notnecessary to give here the details of the method ofshooting and hauling these heavy trawls
, as this shouldnot be attempted excepting with a specially fittedvessel and under expert direction .
The following in struction s’
m ay be useful for working
304 DREDGING AND TRAWLINGa small otter trawl from a small vessel
,without special
fittings . Such a trawl is most conveniently workedwith two bridles and a single towing warp
,as in
the case of a beam trawl . Each otter board Shouldnot be heavier than can be conveniently handled byone man .
The following dimensions apply to what is perhapsthe largest trawl that can be conveniently worked inthis waySquare : 1 1 5 feet long ; 1 40 meshes down to 1 40 ;
mesh, 2 inches .
Top wings , 1 7 feet long ; 36 meshes down to 1 2 ;
mesh, 2 inches .
Bottom wings 27 feet long 30meshes down to 28mesh , 2 inches .
Eatings : 1 40 meshes down to 50 ; length , 20 feet
(7 7 5 feet to head of pockets , 8 5 feet of pockets ,8 5 feet 1 40meshes down toBelly braided same as batings .
Cod end 50meshes across 1 inch mesh 6 feet .Head rope 40 feet .Ground rope 46 feet .
Length of spans used 40 feet each span .
Size of otter boards 3 feet 5 inches x 2 feet2% inches .A trawl of this pattern may be shot over the stern
of the vessel . To prepare the trawl for Shooting ,attach the head line and ground rope to the two boards ,Shackle one bridle to each otter board ,
and then attachthe other ends of the bridles to the towing warp bymeans of a freely working swivel . When the cod end ofthe net hasbeen tied ,
steam slowly ahead and p ay the netoverboard
,starting with the cod end . One man should
be in charge of each otter board ,and should stand on the
outside of the bridles . When the net is trailing away
CHAPTER X
FISHES AND FISHING*
BY L . W. BYRNETHERE are perhaps no living creatures which are moreconstantly brought to the attention of any person livingon or near the sea than fishes
,and yet there are not
many groups whose habits and life-histories requiremore elucidation . Our knowledge of the growth andappearance of the young stages of even the commonestfishes of our own coasts has only been acquired withinthe last quarter of a century
, and there are still speciesof no mean commercial importance of whose breedinghabits we are almost completely ignorant .
The persons for whom the present work is primarilyintended may well have neither the opportunity northe leisure to make exhaustive collections of specimensof fish, and our endeavour in the following pages is todirect attention to the class of Observation that islikely to prove both interesting to the actual observerand useful either to the student of ichthyology or thepractical fisherman .
Whatever the nature of the observation made , it isobviously of the first importance that the species offish under observation should be correctly identified .
The author of this chap ter desires to m ake particu laracknowledgm ent of the advice and assistan ce given him byMr . E . W . L . Holt, on e of the In sp ectors of Irish Fisheries .
306
DESCRIPTION OF FISH 36 7
To insure this , the safest plan is to preserve at leastone specimen of such fish ; but as any individual ,however carefully preserved , is almost certain to undergo some post-mortem change of shape , and to losethe colours which adorned it in life , it is well , whereverpossible
,to take careful measurements , and make a
sketch or note of the colours of the living or freshanimal . This is important , both in the case of colours ,which frequently differ in the two sexes , and are nearlyalways subj ect to change at or shortly after death ;and also in the case of delicate scales or fins, which areeasily damaged .
Fig . 203 is intended to Show the more salient pointsin the external topography of a fish , and the names bywhi ch they are commonly referred to in descriptiveliterature .
In taking the measurements of a fish the acceptedmethod is
,not to follow the contours of the body, but to
measure between perpendiculars, as shown in Fig . 204.
The measurements ordinarily used in descriptions arethose there Shown , and , in addition , the distance between the eyes (measured by callipers or compassesbetween their bony orbits) , and sometimes the greatestbreadth of the head and body respectively . Thesemeasurements should be taken in centimetres andmill imetres .In addition to these measurements it is usual in
the case of Teleostean fishes to count the number ofrays in the dorsal and anal fins, discriminatingbetween Spines and soft rays, an d the number ofscales (when present) in a longitudinal series alongthe body above the lateral line and in a transverseseries from the back to the belly at the deepest partof the body .
In cases where there is more than one dorsal or anal
308 FI SHES AND FISHING
3 1 6 FISHES AND FI SH INGfin , the number of such fins and the number of rays ineach should be noted .
When from lack of time it is impossible to take theactual measurements of a series of specimens
,their
proportions should be noted (for example , eye goesfive and a half times into head head
, six times intolength without caudal fin , etc . ) but even where it isonly possible to note proportions in this manner
,the
total length of the specimen examined Should alwaysbe recorded .
It is well to adopt some regular method of recordingmeasurements in tabular form ,
any particular notesas to maturity , coloration , shape of fins
,or other
matters requiring note , being added at the foot ofthe list of measurements . The general practice is toindicate Spinous fin - rays by Roman figures
,and soft
fin - rays by Arabic numerals , and to insert a comma tomark a break in the continuity of a fin .
The copy on p . 3 1 1 of actual measurements and notesas taken should help to explain this .
Before deal ing in detail with the special points towhich we think the attention of an observer of fishesshould be directed , and
‘
with the necessary gear , itseems convenient to commence with a very brief account oi the best methods of searching for fishes inlocal ities of different natures , even if the informationmay have to be repeated hereafter .To begin at the very margin of the sea , num erous
fishes are to be found between tide-marks on rocky
shores. In searching a locality of this nature , it is ,
as a rule,not much use beginning far above half- tide
mark,unless large and sheltered rock-pools are to be
found at higher levels . The Site selected for examination should be as Sheltered as possible , and , even onbare and exposed coasts
,gu llies and crevices among
SHORE COLLECTION 3 1 1
the rocks may often be found in which there is a considerable growth of weed , of Sponges, and of otherencrusting animal growths sufficient to shelter thesmall animals upon which fishes feed, as well as thefishes themselves .
SPE CIE S—G . MINUTU5 ; LOCAL ITY—IN ISB OF IN ,AUGUST .
Sex
Length (mm )Length with
caudalHead
Sn out
Depth of bodyD ep th of caudalpedunc le
Fin rays , dorsalan al
Scales,long °
ser iestransverse :ser ies
All sp en t : (5 ) with som e sm all r ip e sp erm atozoa . Veryslight traces of dark p igm en t on undersides of cf spot on
Sp in ous dorsal slightly m ore inten se '
in 3 He ight and
shap e of soft dorsal S im ilar in both sexes .
Itmust be remembered thatmany Shore fishes normallySpend the period of low water in very small and shallowpuddles, or even on a patch of bare sand or fine gravel ,provided the Spot is sufficiently protected from the sunby sheltering rocks or boulders carrying a growth ofweed or encrusting animals . Stones and boulders
,of
the Size of a man’
s fist , or larger , should be lifted , even
3 1 2 FISHES AND FISH INGwhen loosely packed to the depth of 1 or 2 feet , andthe smal l pools or wet hollows under them examined
,
from,half- tide mark downwards ; hollows or pools
under the shelter of growing weed or rocky ledgesshould also be searched with a hand net (see
P 3 34)Larger rock-pools can be similarly searched by dint
o f wading , or , if too deep for this , by dangling a baitupon a small hook in front of likely looking hollowsand crevices , the fisherman being careful to keephimself out of Sight .The roots of such seaweeds as have large tangled
and bulbous roots will often repay examination,and
are not infrequently selected as nesting sites by somefishes .
On sandy and muddy shores and estuaries the bestSpots for searching are the pools and runnels left bythe receding tide
,preferably such as from their situa
tion alter little in depth and position from tide to tide .
The hand net already alluded to can be used in suchlocalities
, as can any form of shrimp net .
Below tide-marks and in shallow water , sandy and
muddy ground can be efficiently searched with almostany form of shrimp net or shrimp trawl (see p .
or by a tuck net or hauling seine (see p . accordingto the depth ; especial attention should be paid tobeds of sea grass or weed , and to the immediateneighbourhood of ledges or patches of rock .
As the water deepens,recourse must be had to larger
and heavier trawls (see pp . 295 which can beused on any ground not so uneven or rough as toprevent the ground rope gripping the bottom or to tearthe net .
The weed-covered sides of piers and quay-walls willoften prove excellent hunting grounds if carefully
3 14 FISHES AND FISH INGmeans of a suitable trawl or dredge (see Chapteror by long lines . Various forms of fish trap have beentried for fishing under such circumstances
,but we are
unaware of any such implement suitable for use byany vessel which does not carry a Special equipmentfor deep—sea exploration .
Habits of Fishes.
From the nature of their haunts it is not always easyto observe the habits of fishes in a wild State , but suchmatters as the nature of their food (ascertained byexamination of the contents of their bellies) , breedingseason (tested by the development of roe or milt) , andseasonal movements (as shown by their presence orabsence in a particular locality at different times ofyear) , should ordinarily be susceptible of ascertainment .Other matters as to which information may some
times be obtained are the nature of their haunts,whether at the surface or the bottom , on mud , san d ,
gravel , or rough groun d ,or among coral or rocks ;
the depth at which they are ordinarily found and theirpredilection for salt
,brackish
,hot , cold ,
clean , orturbid water . At times such observations may n ecessitate the use of special gear (closing tow nets) , thetaking of temperatures , or the testing of the salinity ofany particular part of the sea but the necessaryinformation may often be obtaIned by the use ofsimple sounding apparatus or even by ocular observation , while the statements of fishermen on such subj ectsare often both precise and accurate .
In places where the usual commercial fisheries areconfined to in - shore waters , and especially where theirmain obj ect is to supply a local market , seasonal
POINTS To NOTE 3 1 5
changes Of venue and gear in native fishing operations,
and of the kinds of fish brought to market , will oftenafford useful information .
Among Shore fishes, the observations of breedinghabits, to which allusion will be made later , is oftenboth easy and interesting ; and , at whatever depth afish is captured , sexual differences of form or colourmay be observed and noted by comparison of examplesof both sexes
,especially such as are shown by their
roes or milt to be approaching the breeding season .
As an observation of such sexual differences is of thegreatest importance to systematists , and can best bemade in a living or fresh example
,we may briefly point
out the details which demand attention1 . The presence of external copulatory appendages(as in Sharks
,rays
,and chimaeroids) , or of a prominent
genital papilla .
2 . Outgrowths of the scales or dermal covering , anddifferences in the teeth .
3 . Differences in the profile of the head and back .
4 . Elongated fin rays (especially of the dorsal andanal fins) .
5 . Thickening of the rays of the pectoral , ventralor anal fins .
6. D ifferences in size .
7 . D ifferences in coloration .
8 . D ifferences in the arrangement of the luminousorgans of oceanic fishes .
Attention should further be paid to the size at whicheach sex commences breeding
,to the comparative
abundance of Specimens of the two sexes,and to the
permanent or transitory nature of the sexual differencesobserved .
In many fishes colour changes may occur withstartling rapidity
,especially under the influences
FI SHES AND FISHING
of Shock or excitement . Such changes are,perhaps
,
best observed in captive examples , and may often benoticed if a fish is kept in a bucket on deck for ashort time after capture .
Eggs.
Sharks and rays and allied fishes are either viviparous or else lay large eggs enclosed in horny capsulesor purses (Fig. the dissection of pregnantfemales will often serve
,in viviparous species , to Show
how many young are born in one litter ; or , in oviparous species , to connect an egg capsule with theparent fish .
Teleostean fishes, although sometimes viviparous ,usually produce a comparatively large number ofsmall eggs
,examples of which are Shown in Fig . 207 .
These eggs may be either pelagic —that is ,
buoyant and floating in the water at whatever depthor demersal —that is , attached to some obj ect , orlying among gravel or débris at the bottom .
The pelagic eggs of different species of fish vary fromabout to 2 millimetres—in diameter , while demersaleggs are commonly somewhat larger, and are seldom lessthan about 1 5 millimetres in diameter . Their diameteris most easily measured by putting them under a microscope of low power , with an eyepiece ruled in squaresof about 0-05 millimetre value with the obj ectiveemployed .
It should be remembered that the eggs of teleosteanfishes are very readily fertilized artificially, if ripe examples of both sexes are forthcoming for the purpose .
To effect artificial fertilization , all that is necessary isto stroke gently the belly of the fish from in frontbackwards until eggs or milt are extended , and to
3 1 8 FI SHES AND FISHING
in j ars of clean sea water of the proper salinity andtemperature , occasionally changed . They are
,how
ever , very susceptible to sudden changes of sal inity ortemperature , and care must be taken not suddenly tochange them from chilly and saline water of the opensea to the warmer and fresher water of a harbour ;such errors and consequent disappointment can generally be guarded against by the use of a little care .
Demersal eggs are occasionally laid either loose orin adhering masses on the sea bottom
,and left to
hatch (as in the case of the herring) but are more comm only laid either in masses or in an even layer , andcared for by the parent (usually the male) during theprocess of incubation . Many shore fishes, and somenormally living in deeper water , construct nests, orguard or carry about their eggs during development .
Instances of the latter habit may be found in thepipe fishes and sea-horses , in which the male carriesthe eggs in a pouch or groove in the belly and in somecatfishes and perciform fishes , in which they are carriedin the mouth or throat .
The line between what may be termed nest -buildingand the mere guarding the eggs is not very easy todraw .
In some cases sticklebacks and some wrasses) amore or less elaborate nest of seaweed or other materialis formed ; in others (Lepadogaster and some blenniesand gobies) an empty shell (Fig . 206) or the hollowbulbous root of a seaweed is selected again, \the fishmay overturn a Shell , so as to form a hollow beneath it ,and then conceal the chamber so formed with a covering of sand
,or may be contented with a crevice iii a
rock or overhanging stone . We have known the hollowat the foot of a recording thermometer lifted dailyfrom the harbour where it lay , tenanted by a small
LARVZE AND YOUNG 3 1 9
goby and his brood . From such examples as thesethe step to those cases in which the eggs are laid in a
more or less exposed situation , and merely guarded bythe male parent , is a very short one .
When Shore collecting , or dredging , or trawling inshallow water , it is , consequently , well carefully toexamine crannies in rocks , the undersides of stonesand old shells
,tins , old bottles, and any other likely
sites . Very frequently the secret is disclosed by thediscovery of the dutiful parent , and by his reluctanceto leave his charge . Often enough the assiduity ofthe male in defending his charge , and sometimes evenhis courtship , may be observed in the pool in which heis found but matters are facilitated by removing himand his brood into a tank or large shallow dish .
Larvae.
The newly hatched larvae of fishes are , like pelagiceggs
,commonly taken in tow nets , and careful observa
tion is required to enable these to be connected withspecimens hatched in captivity from the eggs of knownparents , or with the older stages which gradually leadto the attainment of the form and characteristics of theadult fish .
Fig . 208 is intended to Show the ordinary appearance and main characteristics of the pelagic larvae ofteleostean fishes .
Young.
The young of fishes are often very different from theadult in form and colour , apparently especially so inthe case of pelagic fishes . Series of the young of almostany species of fish are useful
,both as a method of ascer
taining the probable rate of growth (where the dates
326 FISHES AND FI SH INGof capture are known) , and as throwing light upon thelife-histories of allied but less known species .
Often the young of a fish are found in localities widelydifferent from those ordinarily inhabited by the adult
,
and,especially in the case of fishes of commercial
importance , records of the places in which the youngare found at various sizes , their comparative abundance , and their seasonal movements , may have a verygreat practical value .
Certain differences in form and proportions betweenthe young and adults of fishes are so constant and wellknown as to deserve mention . For instance
,the eye
of a young fish is , as a rule (and with the known exception of a few oceanic fishes) , proportionately largerthan that of the adult , and consequently bears a largerratio to the length of the head and snout and to theinterorbital width . The form of the young is not infrequently slighter
,
’ and the serrations of the operculum and
preoperculum (if present) may be more strongly marked .
Such characters as an elongated beak , prolongedfin rays
,or a characteristic colour pattern , cannot be
safely looked for in the young , nor can the elongatedfin rays of some larvae be expected to persist . On theother hand , the number of fin rays and scales is normally very constant thr oughout life , and , once thelarval phase is passed , the positions of the insertionsof the paired fins seem to change but little , howeversubj ect to modification their shape and the relativelengths of their rays may be .
Oceanic Fishes .
We advisedly combine under the above heading all
the fishes of the open ocean , whether i nhabitants ofthe bottom
,the surface , or the intervening waters ,
3 22 FISHES AND FISHING
F IG . 207 .—I
,2
, 3 , PELAGIC EGGS (D IAGRAMMATIC) ‘
x 40 ca:
4 , D EMERSAL EGG OF GOBY (AFTER PETERSEN ) 5 , D EMERSALEGG OF SPOTTED SUCKER (AFTER HOLT) x 30 ca .
2 . Aud itory cap su le . n . Notochord .
a .h. A ir bladder . o .g. Oil globu le .
Attachm en t filam en ts . p .f. Pectoral fin .
B lastoderm . y . Yo lk .3 . Eye . Zon a radiata .
324 FISHES AND FISHINGficial 100 or 50 fathoms of the ocean provide valuablerecords
,but the lack of any net at once capable of
capturing any but the youngest and smallest fishes,
and of being opened and closed at ascertainable depths,
leaves us practically in absolute ignorance of the inhabitants of the middle depths of the ocean . Series ofhauls taken at the same spot with Similar nets fishedopen from different depths , may afford some evidenceof the horizon at which a species is most abundant .Some Slight evidence on this subj ect has been derived
from closing tow nets ; but a tow net is ill adaptedfor the capture of adult fishes , and it is most unsafe toassume that such adults are to be found at the samehorizon as the larval and young forms of the speciesto which they belong .
We believe that for the capture of such larval andyoung fishes as live in the upper waters of the ocean
,a
tow net should be allowed to sink to about 100 fathoms,
Since existingrecords rather point to the region lyingbetween 100 and 25 fathoms as the normal habitat ofsuch forms
,which are comparatively scarce at the
actual surface . Interesting results could probably beobtained by the use of tow nets Opening and closing atdifferent depths within this region fished by night .Wherever possible , a temperature record , taken at
the depth at which the gear was supposed to beworking
,should accompany observations made in the
Open ocean .
Preservation of Specimens.
Two preservatives are ordinarily employed in thecase
‘
of fishes : (1 ) alcohol , in some form or other ; and
(2) formalin .
Alcohol has the disadvantage of having to be carriedabout
,of a strength nearly that at which it is used it
Gear. *
GENERAL .
Before dealing in detail with the various kinds ofline and net likely to be used by those for whom thiswork is intended , a few prefatory remarks upon thegeneral subj ect m ay prove useful .
1 . All lines and nets, of whatever material , shouldbe oil-dressed or barked , not tarred .
2 . Hooks , swivels , shackles , and other metal articles ,if made of iron or steel
,should be galvanized .
3 . Many of the lines and nets described take up a
lot of room when mounted ready for use it is generallybetter in such cases to carry their component parts
,
and mount them as and when required .
4 . All gear Should be well dried after use before beingstowed away .
5 . Nets in particular constantly need mending , and
any vessel carrying nets should also carry at least oneperson who can mend them .
6. Plenty of spare lines , hooks , snooding , twine ,rOpes , lead (pipe and wire) , corks (or glass floats) , andof anything else likely to be required for repairs orrenewals
,should always be carried .
7 . And lastly ,never despise native gear
,however un
promising in appearance ; for one thing , it is alwayspossible to find someone locally who can make it fishefficiently ; and ,
for another,i t has probably Stood the
test of long use in practice . For exploring any watersin which a commercial fishery is carried on , the hiringor subsidising of those who carry it on will probably,in the long- run
,prove the best way of securing fish .
Exc lud ingtrawls (as to which see Chapter IX . ) and apparatus no t pr im ar ily in tended to catch fishes .
HAND LINES 327
L INE S .Hand lines may be used either with or without a rod .
Quite apart from its sporting aspects , a rod possessestwo advantages (I ) It holds the line clear of the boat ,pier
,or rock from which it is used and (2) it enables
lighter tackle to be employed than if a hand line is used .
For fuller information as to sea rods , reels , and lines ,reference should be made to such books as the Badminton Library volume on sea-fishing but the following brief notes m ay prove usefulThe rod should be stiff and not too long , its metalparts made of phosphor-bronze or some other rustproof metal . It must be remembered that the weightrequired to keep a line on the bottom in a tideway isconsiderable
,and that a long rod is a nuisance in a
boat,and in no way more efficient than a short one .
The reel Should be large and of the ordinary Nottingham pattern , with an optional check . We do notknow that anything is really better than a strongwooden reel with an easily fitting line drum , preferablywith a rust-proof metal flange and back plate ; theworking parts should be kept well greased and the linedrum fit easily, unless backed with metal ; otherwisethe wood will Swell when saturated with sea water,and the drum j am in the flange . The cost should notexceed 10s . or 1 z s .
For lines plaited and barked hemp is quite satisfactory and inexpensive
,costing from 2s . 6d. to 45 . per
100 yards , according to weight ; a twisted line is aptto kink , and should be avoided .
Traces and snoods may be of plain or twisted gut ,horsehair , wire , hemp , or raw hide , according to theprobable weight and biting powers of the prospectivefish .
FISHES AND FISHING
F IG . 209 .—TRA CE s .
I , Sp inn ing trace su itable forusewith a hand lin e with severalsmall leads 2 , sp in n ing trace
for use with a rod or hand lin e3 , trace for bottom fishing.
R , Runn ing lin e ; t, trace
5 , swivels ; l.s . , lead -snood
L . lead .
3 30 FISHES AND FISHINGand stouter than lines used with rods also the use ofplaited lines and swivels is not so necessary . WhenSpinning with a hand- line , it is often more convenientto use several smal l leads than one large one (seeFig . Hemp lines
, 40 fathoms long , should costfrom about zos . to sos . per dozen
,according to weight .
Long lines, Spillers , or bolters , are suitable for use inwater down to 500 fathoms or more . They posses stwo great advantages that they can be used on groundtoo patchy for trawling , and that they can be left tothemselves while the vessel setting them is otherwiseoccupied ; also one very serious disadvantage—thatthey require a great deal of bait .The long line as ordinarily used by English fishermen
for commercial purposes is 40 fathoms in length,and
carries hooks on snoods of from 3 to 5 feet long , fastenedon to the line at intervals of to 2 fathoms . Anynumber of such lines up to twenty dozen (which is thefull outfit of a modern line -fishing vessel) are fastenedtogether end to end , and fished in one string . Theends of the string are made fast to anchors or weightsand their positions marked by buoys ; and ,
in the caseof a long string, further anchors are added at the endof every sixteen lines
,and their positions al so marked
by smaller buoys . Before setting , the lines must becarefully coiled in boxes or shallow baskets (eachordinarily holding eight lines) , and the hooks baitedand so arranged as to run out smoothly without
‘
fouling.
Long lines Should always be shot across a tide, and ,
where possible,hauled at slack water . N0 one who
has not had considerable experience of long lines andtheir ways should ever attempt to set or haul themout of anything but a rowing boat ; and it is well toremember that if lines are set at low water or on a risingtide sufficient slack should be allowed on the buoy lines
LONG LINES 33 1
t o prevent the buoys being drawn under the surface asthe tide rises .
By regulating the distance from the buoys at whichthe lines are fastened to the buoy ropes
,a long line
m ay be set so as to fish at any desired distance fromthe bottom .
By the courtesy of a well-known East Coast firm ,
we are able to give the following estimates of the costof long lines and gear . The detailed prices will givethe necessary information as to the cost of unmountedlines and anything wanted for renewals . Mounted linesare not very easy to stow , and it might be advisable onlyto mount at least a part of the lines as and when wanted .
The prices given are for baskets of eight lines (320fathoms in all) for ordinary use by yachtsmen orothers fishing for Scientific purposes , one or two basketswould probably be ample , and such a string wouldonly require to be anchored and buoyed at the ends .
The weights given are per line of 40 fathoms .
HAL IB UT F I SH ING GEAR .8 5
-
p oun d Ru ssian hem p long l in es , 40 fathom s
long, white , 48s . p er dozen1 60 No . 3 hooks and loop s 2 2s . 6d . p er
1 60 6O- in ch cotton sn oods , tan n ed , 3 5 s . p er
I basket4 p ounds cork 6d . p ou n d
F ixing lin esPer basket
Extra for swivel hooks p er basket
COD F I SH ING GEAR .8 3
-
pound l in es , as above , 305 . p er dozen1 60No . 6 hooks and loop s , 2os . p er
1 60 6o - inch cotton snoods , as aboveB asket, cork , and fixing, as above
Per basket £ 2 0 o
3 3 2 FISHES AND FISHING
HADDOCK OR WH IT ING F I SH ING GEAR .8 2-
pound lin es , as above , 2 1 3 . p er dozen1 60No . 1 5 hooks and loops, 203 . p er
Snoods, basket, cork , and fixing, as above
Per basket £ 1 1 4 o
The following are requ ired for a fu ll outfit of 20 dozen lines
1 5 2 8-pound buoy an chorsI 5 6o
- fathom buoy rop es2 buoy lights1 2 sm all wooden buoys3 large captain buoys1 lin e hau ler1 2 willows for bu oys1 2 yards bunting for buoysPlain hooks , unmounted , Should cost from 5 5 . 6d . to
7s . 6d . per and conger swivel hooks , unmounted,about £ 1 1 8 s . perAs will be seen
,the only item which varies much
in price in lines of various strength is the actual l inesthemselves
,which increase in price according to their
weight .
We believe that Scotch fishermen often use 60fathom lines , five lines to a basket ; these cost about
£1 1 zs . 6d . per basket . We do not know the weight ofsuch lines
,which is
,however
,probably 3 to 4 pounds
per line .
A commercial line fishery is carried on off the Portuguese coast in very deep water , and as the In ethodemployed may be found useful elsewhere , a brief description of the gear examined and described byVaillant follows .
The line used consists of a hauling line , 650 to
700 fathoms long , and about 21 inch in diameter, towhich are fastened twenty to forty hook lines of the
NETS .I . HAND NETS .
Hand nets for use among rocks Should have framesof one of the forms Shown in Figs . 21 1 , 2 1 2 . The form ofring Shown in Fig . 2 1 1 is best adapted for light netsfor general use , or heavier nets for use on sand ormud while that Shown in Fig . 2 1 2 is more suited forheavy nets for use among rocks . The first of thesecould be used with a net of either strong netting orstout mosquito net . Nets of either type , completewith handle , should cost from 4s . to I OS . , according tosize and make .
On sandy or muddy ground much larger nets can beused , and many forms of such nets are locally used indifferent parts of the country for shrimping the largeShore nets used for this purpose on the Lincolnshirecoast
,which are about 10 feet in the beam and have
9- feet handles , cost about £1 10s . complete .
2 . D IP NETS .Dip nets are nets mounted on circular rings lowered
into the water by means of a pole , and baited . Theyare left stationary until a fish enters , and are thenrapidly lifted above the surface . Small nets of thistype , mounted on galvanized iron rings 24 to 36 inchesin diameter
,and costing with the necessary lines about
10s . to 1 5s . each, are commonly used for ‘ catching
prawns,and are suitable for taking small fishes in the
neighbourhood of rocks (see Fig . A net of thispattern would probably be improved by the additionof a second ring
,which would enable it to collapse on
the bottom without fouling . Much larger nets
DIP AND GILL NETS 3 35
mounted on wooden or wire rings , and , where necessary,
baited , are commonly used abroad for taking small
F IG . 2 1 3 .—D IP NETS .
fishes in Shallow water ; such a net , a fathom in diameter
,ought not to cost more than 1 5 s . or so , and
larger nets in proportion .
3 . FIXED NETS .Gill Nets.
—The simplest form of fixed net is thegill n et, or splash net , which is simply a net of suitablemesh for the capture of the fish, mounted very slackon the head and ground ropes . The ends of the netare made fast to some fixed obj ect or anchored , theirpositions , where necessary , being marked by buoys .
The head rope carries sufficient corks or glass floats tokeep it at the surface , and the bottom rope must besufficiently weighted to hold the bottom . A gill netwill , of course , only catch such fish as are of a size to
336 FISHES AND FISH INGmesh themselves , and , to prove efli cient, Should be setso as to fish by night .
A well-known firm has kindly supplied the followingquotation
,which will serve as a guide to cost
Sp lash-net, 70m eshes deep—Le 8 to 9 feet deep—25» in ch
m esh, p ly
- cotton , barked and m oun ted on two lin eson top and bottom ,
corked and leaded ready for fishing,
7d . p er yard .
A train of drift nets , such as that next mentioned,could be moored so as to fish as a gill net
,if a properly
leaded ground line were fastened along its foot ; buta drift net is ordinarily rather deep for use as a gi ll net ,and is not always mounted along the foot .
The pollen fishers of Lough Neagh use gill nets
(locally termed trammels made of exceedinglylight but strong linen thread these nets are made atLisburne , and possess the advantage over either hempor cotton nets of stowing into much smaller Space andwearing better . In cases where economy of room isimportant , it might be well worth while to have netsmade of linen thread .
Drift Nets (Fig . 21 4) are similar in their operations togill nets
,but are constructed tofish at or near the surface ;
they are not moored , but drift on the tide . For commercial purposes a train of drift nets , often far over a milein length , is used these nets are fastened end to end
,
and carry sufficient cork on the head ropes to keep themupright in the water , but not necessarily to keep thehead rope at the surface . At frequent intervals buoysof wood or canvas are fastened to the head rope
,and
the length of the buoy lines regulates the depth atwhich the nets fish . Drift nets may or may not bemounted on a foot rope in shallow water , where theground is rough ,
the absence of such a mounting m ay
3 38 F ISHES AND FISH INGspond. The middle net is twice as long and twice asdeep as the two outer ones , has a very much smallermesh ,
and is mounted very slack on the head rope .
The result of this is that a fish, coming in either direction , on striking the net , carries a portion of themiddle net through the large mesh of the outer wall
,
and is thus trapped and held . For commercial purposes , the walls of a trammel are ordinarily some 40 to
50 fathoms long , with a 9 or I O- inch mesh betweenknots , and a depth of twelve to twenty meshes ; themiddle net is 80 or 100 fathoms long
,but set on a head
rope of the same length as the walls , and has a meshof about 2 inches , and a depth of some fifty or sixtymeshes . The length and depth of the net and Size ofmeshes must be varied according to the probable sizeof the prospective fish .
A Scotch firm of net manufacturers has kindly supplied the followmg estimate
Tramm e l, 9 feet deep ,
barked and m oun ted on 1 5-thread
rop e on bottom , and 9-thread rop e on top ,
corked and leadedready for fishing,
1 s . 5 d . p er yard . D im en sion s : two outsidep ieces , 20 m eshes deep , 9
- in ch m esh ,2 1 -
p ly cotton . In sidep iece ,
1 20m eshes deep ,2 i - in ch m esh , p ly cotton .
Like other fixed nets , trammels should be used bynight ; they are not easy to dry properly,
and consequently liable to rot if not very carefully treated .
Moreover , cleaning a trammel after use on weedy orcrab - frequented ground is a task calculated to try thepatience of J ob himself .In ordering any fixed net, the maker should be told
the purpose for which it is intended , as a clue to thesize of mesh required ; probably the mesh could bebest described by giving the size of fish anticipatedag East Coast herring , Spring mackerel , orpollack .
”
DRIFT AND SEINE NETS 3 39
2 14 .-PART OF TRA IN OF D R IFT NETS (D IAGRAMMATIC) .
Shor e
F IG . 2 1 5—SE INE NET .
F IG . 2 1 6 .—END OF A SE INE NET.
346 FISHES AND FISH INGSeines.
—A seine , or scan , is a long , comparativelyshallow net , which is so shot that it can be drawn overa certain area of ground or water in such manner asto capture anything within that area . For the purposes oi this chapter , all seines other than those fishedfrom the Shore may be disregarded . The head ropeof such nets must carry sufficient cork to float buoyan tly , and the ground rope be so weighted as to holdthe bottom . The head and ground ropes are generallykept in their relative positions , and held apart whilethe net is being hauled by poles at the ends of the netround which they are hitched (see Fig . Such netsare commonly shot from a boat which is rowed out fromthe shore and back again , the end of one hauling ropebeing le ft on the shore during the shot (A in Fig .
and the end of the other landed some distance away
(B in Fig . The net is then hauled ashore,the two
ends being brought closer to one another during theprocess
,until the central part of the net is finally
brought ashore about midway between the points at
which the hauling ropes were originally left and landed .
A tuck seine only differs from a seine in having a bunt ,or bag (analogous to the cod end of a trawl) , in itscentre
,which collects the fish and prevents their escape .
Seines and tuck seines are principally of use for catching fish on a smooth strand , particularly on a graduallyshelving beach or in an estuary . They are most efficient if fished by night or at low-water springs , and ifthere is any appreciable tide or current , the ‘boat mustbe rowed against such tide or current while shootingthe net .
For commercial purposes seine nets which have nobunt are frequently used , but such nets require verycareful handling
,and are not suitable for
en ced. On the other hand, a tuck seine
342 FISHES AND FISHINGwhich is sufficiently fine to retain small fishes andsufficiently strong to stand the strain of fishing . As
ordinarily constructed , it has a rectangular mouthabout 7 feet wide by 5 feet deep , a length of about2 1 feet , and tapers to an opening of about 2 feet indiameter at the cod end . The sides of the mouth are
laced on to stout wooden poles, and the net is kept
open while fishing by otter-boards (see p . whichare j oined by ropes to the head an d foot of the poles .
A net of the size above described can be obtainedin Denmark at a cost of about 1 40 kroner 10s ) ,and the poles , weights , and boards for about 65 kroner
The material of which the Danish nets aremade is apparently woven of coarse linen thread and
F IG . 2 1 7 .
—PETERSEN ’S YNGEL -TRAWL OR Y OUNG-FI SH N ET .
has about 1 25 meshes to the metre , costing 2 kronerper metre . Similar nets made of Manchester screwcloth have proved quite satisfactory and are muchcheaper
,as about 50 yards of material at about 7d .
per yard are required and the cost of makin g up by a
sail-maker should not exceed £1 , thus reducing thetotal cost of the net to about £2 1 os .
In fishing the net in deep water a heavy lead weight(ordinarily about 40 pounds) should be att
ached tothe shackle fastening the spans to the hauling warp ,
and the otter-boards must always be well weighted .
The net m ay be shot from a Single block with a littleway on the vessel
, and the otter-boards loweredtogether
, as ,if properly weighted , they spread as soon
as they are in the water .
YOUNG-FISH NET 343
Surface hauls should only be of short durationfifteen minutes) , as the net soon becomes choked
with j elly-fish, salps , and the like,but in deep water
hauls of less than an hour’s duration cannot be ex
pected to give much result . The net m ay be fishedactually on or just clear of the bottom with goodeffect , but is very liable to injury if so fished .
M ISCELLANEOUS GEAR .
Some fishes m ay be taken in crab or lobster potssuitably baited ; probably the pots made of nettingstretched over a metal or wood frame are better thanthose made entirely of osier .
Narrow and Shallow creeks and channels m ay befished by stretching a short gill net across them , andbeating the water up towards it by wading in linewith poles and Splashing , or by dragging another n ettowards the fixed one .
CHAPTER XI
PRESERVATION OF MARINE ORGANISMSBY E . J . ALLEN AND EDWARD T . BROWNE
Introduction .
IT is impossible within the space allotted to thissection to describe in any detail all the numerousmethods for the preservation of marine organisms .We have selected the simplest methods
,which
,if care
fully carried out,should yield good results . Those
who require their specimens preserved by refinedmethods for minute microscopical investigations arestrongly advised to consult that indispensable book
,
The Microtomist ’s Vade-Mecum , by Dr . A . BollesLee . This book should be in the hands of every marinenaturalist
,and we have frequently consulted its pages
for this chapter . We are also indebted for methodsto Dr . S . F . Harmer and Mr . R . L . Leiper
,and
especially to Mr . A . J . Smith , who has charge of thePreservation Department in the Marine Laboratory atPlymouth .
The subj ect matter of this chapter is really‘
in twoparts . General information and simple methods suchas are within every traveller
’
s power are printed inlarge type but the more technical and delicate methodsof preservation
,for detailed microscopic study rather
than faunistic collection,are printed in a smaller type
3 44
346 PRESERVATION OFimportant factor in the success of fixation is thepenetration of the
'
chem icals through the tissues .
penetration gives time for the innermost cells or tissuesto undergo post-mortem changes be fore they are
properly fixed .
The preservation of an animal after death,or of its
tissues after fixation ,is the final stage in the prevention
of decay . The preserving fluids commonly used areeither formalin or alcohol , and their preserving actionshould be understood . We take as an example a bigj elly-fish
, the j elly Of which is more than 90 per cent .water . When alcohol is used as the preserving fluid ,
all the water in the j elly has to be turned out,and
alcohol of a different strength substituted . The firstbath of al cohol is considerably reduced in strength bythe water from the j elly . Fresh alcohol is then sub
stituted,and this second bath becomes less diluted .
The changing of the alcohol must go on until one issure that the Specimen is thoroughly saturated withal cohol of at least 70 per cent . strength . Weak solutions of alcohol have no preserving qualities , and arenot proof against bacteria .
Formalin,on the contrary ,
is a watery fluid , and ithas Simply to mix with the watery fluids inside thej elly . During the process of mixing its originalstrength is lessened by dilution , as in the case ofalcohol , and a certain quantity is used up in chemicalaction on the tissues . But so long as there is a smallpercentage of formalin present the j elly is safe againstdecay
,owing to the powerful antiseptic properties of
formalin .
CHEM ICALS
I . CHEMICALS USED IN PRESERVATION .
A . PRE SERVING FLUID S : Formalin ,alcohol
,formol
alcohol .B . F IXING FLUID S : Corrosive sublimate
,picric
acid , picro- formol , chromic acid ,
Flemming ’ ssolution ,
Hermann’
s solution , osmic acid .
C . ANAESTHET ICS : Cocaine , menthol , alcohol .
A . PRESERVING FLUID S .
Formalin (Formaldehyde, Formol) .—Formalin andformol are commercial names given to a solution offormaldehyde
,which is a gaseous compound
,HCOH,
in water . This solution , when first placed on themarket , contained 40 per cent . of formaldehyde , butit was found that at this strength the solution wasliable to undergo chemical changes and to throw downa precipitate , whereas a weaker solution remained un
changed . The solutions of formaldehyde now varyfrom 30 per cent . to about 40 per cent . Form alin is a
powerful antiseptic,and is manufactured on a large
scale for disinfecting purposes even a very weaksolution has a deadly effect upon bacteria . It can beobtained from retail chemists andp hotographic dealers ,but when large quantities are required it is advisableto purchase it directly from a manufacturing chemist ,and at the same time to ascertain the strength of thesolution . Formalin requires careful handling ; itsvapour has an irritating effect upon the nose and eyes,but
,fortunately
,the irritation soon passes away with
out doing any harm . The action of the solution uponthe hands is to harden the skin and to make it Slightlyrough . Weak solutions, as a rule . are not injurious ,
348 PRESERVATION OF MARINE ORGANISMSbut it is advisable to wash one
’
s hands directly afteran immersion in formalin, and never to allow the
30 per cent . solution to dry into the skin . There are ,
however,people whose Skin is seriously affected ; the
Skin breaks , after the manner of chilblains,with deep
,
open cracks , which are painful , and take some time toheal and the fingers feel numb . None of these effects
,
however , are permanent , or in the slightest degreedangerous .The hardening and preserving properties of formalin
for animal tissues were discovered independently byBlum and Hermann in 1 893 , and probably no one hasbeen more benefited by this important discovery thanthe marine naturalist . Previous to 1 893 alcohol waspractically the only fluid used for the preservation Of
marine animals . It must not be supposed that formalin has completely supplanted alcohol
,though the
qualities of the former have been loudly praised andthe existence of alcohol almost forgotten by somenaturalists .
Formalin has two great advantages over alcohol :
(1 ) It does not usually produce a Shrinkage of thetissues therefore it is a sp lendid fluid for the preservation of delicate
,soft-bodied animals
,such as j elly
fishes . (2) It is a great time - saving fluid ,as specimens
can be placed straight into formalin without requiringany further attention whereas with alcohol it isusually necessary to pass specimens through a seriesof different grades of strength
,each grade requiring
a certain length of time,or to change a strong grade
several times so as to get rid of the watery fluids withinthe specimens .
To marine naturalists formalin has two special advantages (1 ) It can be diluted with sea water, as wellas with fresh water . When alcohol is mixed with sea
3 50 PRESERVATION OF MARINE ORGANISMSof marine animals , it is necessary to make quite clearthe difference between form aldehyde
'
ro per cent . andformalin 10 per cent . Formalin
,as purchased
,con
tains a definite quantity of the gaseous formaldehydedissolved in water , and the percentage of form alde
hyde present should be stated on the manufacturer ’slabel thus : Formaldehyde 40 per cent . To makeup a solution so as to contain 10 per cent . of form alde
hyde we must add three parts of water to the quantitytaken out of the 40 per cent . stock bottle c .c . offormaldehyde 40 per cent . 300 c . c . of water) . Butif we make up a solution to contain 1 0 per cent . offormalin
,then to the quantity taken out of the bottle
labelled Formaldehyde 40 per cent .
” ‘we add nineparts of water (100 c .c . of formaldehyde 40 per cent .
900 c .c . of water) . This 10 per cent . solution offormalin is equivalent to formaldehyde 4 per centand formaldehyde 10 per cent . is two and a half timesstronger than formalin 10 per cent .
Both methods of making up working solutions arein use and as authors frequently use the term sformaldehyde and “ formalin indiscriminately
,
without giving a clue as r to whether the percentagesrefer to form aldehyde or formalin , there is consequentlymuch confusion .
There Can be no doubt that the scientific method isto reckon the percentage in the quantity of form alde
hyde present,especially as the commercial solutions
of formaldehyde now vary from 30 to 40per cent .
Formaldehyde 10 per cent . is a constant strength ,
whereas formalin 10 per cent . is liable to vary in theamount of formaldehyde present , according to thestrength of stock solution .
The unscientific method of making solutions prevails
,partly because all commercial solutions were sold
FORMALIN 3 5 1 .
for many years as 40 per cent . strength ,and partly
because it is very easy to read percentages in a centimetre measure .
Successful preservation with formalin depends uponusing sufficient form aldehyde to fix every cell in thespecimen
,and a surplus sufficient to prevent subse
quent maceration . A specimen which is properlyfixed and preserved in 50 c . c . of formaldehyde 4 percent . can also be fixed and preserved in 50 c .c . offormaldehyde 2 per cent .
, providing that the lattersolution be changed once . I t is much the safest planto allow the specimen to soak for two or three days informaldehyde 2 per cent .
, and then to change it intoformaldehyde 4 per cent . I t is a great mistake to bestingy over the formalin ; use it freely , and changethe solution at least once , or , if this cannot be done ,make up the strength by adding a very small quantityof the strongest formalin .
There can be no doubt that collectors , as a rule , donot use sufficient formal in , and forget that their specimens are very liable to remain untouched for two orthree years . Specimens which are worth a place in a
permanent collection are worth a little extra troubleand a little extra form alin .
Concerning the strength of the solutions of formalinfor preservation there is a difference of opinion .
Some workers use weak and others fairly strongsolutions . A good
,useful solution for general work
is formaldehyde 4 per cent which is made up thusFormaldehyde 40 per cent . (or about 40 per1 part ; water, 9 parts . The bottle may be labelledeither “ Formalin 10 per cent . , or Formaldehyde
4 per cent .”
If the commercial solution is purchased at 30 percent . strength
,then the following proportions should
3 52 PRESERVATION OF MARINE ORGANISMSb e taken Formaldehyde 30per cent .
, 1 part water,
63 parts . This solution contains formalin 1 3-
3 percent . ,
and is equivalent to formaldehyde 4 per cent .
Some animals can be killed at once by droppingthem into formalin 10 per cent . , or by pouring thesolution into the sea water containing the animals ;but others are not killed quickly enough
,and have
sufficient time to contract or to cast off appendages .
For the latter class of animals either an anaesthetic,
like cocaine , may be used before adding the formalin,
or another chemical , like picric acid , added to theformalin ,
to quicken the killing action .
The value of formalin in fixation is to preventShrinkage , and for this purpose it has been added withsuccess to several well-known fixative formulaAlcohol . —The alcohol used for preserving purposes is
pure methylated spirit , known as Industrial methylatedspirit
,upon which excise duty must be paid within the
limits of the British Excise , or an exemption permitobtained from the Custom House
,London . The
ordinary methylated spirit obtained from a dealer isquite useless for preserving marine animals
,as it con
tains certain chemicals , put in to prevent people fromdr inking it . Directly water is added to this liquid ittakes on the appearance of milk , and a very fine precip itate is thrown down . All attempts to get rid ofthis precipitate are only waste of labour , as anadditional drop of water starts a fresh precipitate in afiltered solution .
Pure methylated spirit when purchased is commonlycalled 90 per cent . alcohol ,
” though its strength maybe Slightly greater than 90 per cent . This may bediluted with water so as to make up solutions containing 30 per cent 50 per cent . ,
and 70 per cent . ofalcohol . These solutions can either be made up by
354 PRESERVATION OF MARINE ORGANISMSVolumes of water equal to the difference between thepercentage desired and 90. Thus
,to make 70 per
cent take 70 volum es of 90 per cent . ,and add 20 of
water to make 50per cent . , take 50 volumes of 90percent . ,
and add 40 of water andSo on .
All solutions of alcohol Should be made with purefresh water (ordinary ship
’s water should be filteredfirst , even if distilled) . Water loaded with mineralsalts gives a precipitate when mixed with alcohol
,and
unless the precipitate is removed by filtration ordecantation the specimens generally become coatedwith a very fine dirty sediment .
Alcohol by itself is not good for fixing purposes,
but is generally used in combination with otherchemicals , as it increases their penetrating power . Itis a good hardening agent
,but unfortunately it pro
duces a considerable am ount of Shrinkage in the tissues .As a preservative it is excellent
,and the safest of
all preservatives for specimens intended for permanentcollections . Though formalin is its strong rival , stillformalin is a newly discovered fluid and a rather unstable one
,and we have yet to find out how long its
preserving qualities are ‘
going to last . Hydroids andMedusm which have been in formalin 10 per cent . fortwelve years Show no visible signs of deterioration .
The strength of the alcohol commonly used for thepreservation of animals lies between 70 and 80 percent . The minimum strength should be rigidly fixedat 70per cent . A slight increase over 70per cent—say
75 per cent .
—is an advantage,because it provides a
margin against evaporation .
Delicate , soft-bodied animals Should not be placedstraight into 70 per cent .
,but first into 30 per cent .
alcohol for a few hours,and then in 50 per cent . for
several hours , and each solution should be changed at
ALCOHOL 3 55
least once . Transfer from 50 per cent . to 70 per cent .
The passage through these different grades of alcoholreduces the amount of Shrinkage , and gradually re
moves the watery fluids from the body of the animal .It is very important for all the tissues of the body to bethoroughly permeated with 70 per cent . alcohol
,hence
the necessity of changing at least once the 70 per cent .solutions . As weak solutions of alcohol quickly produce maceration of the tissues , it is advisable not toleave specimens too long in the weak grades .
Alcohol which has become weakened by water fromthe animals soaked in it (so long as it does not containchemical s) should be kept , and coarse animalsCrustacea ,
fish, starfish , etc .
—can have their firstbrief soaking in this before being transferred to strongeralcohol . An alcoholometer is useful here . This spiritshould be thrown away when of a less strength than
30 per cent . But if it is not necessary to economizealcohol , then animals with hard coats
,such as crabs
,
or with firm bodies , such as fishes , can be placed at
once in 70 per cent . after a preliminary soakingthe alcohol must be changed . The number of changesrequired depends upon the size of the animal and thequantity of alcohol used for each bath . The mostimportant thing is to keep up the strength of the finalsolution
,and not to store away the specimens until
they have become thoroughly permeated with at least
70 per cent . alcohol .I t is well to remember that the weakest grade of
alcohol is the heaviest , and remains at the bottom ofthe vessel . When passing specimens through differen t strengths of alcohol , an occasional stir up shouldbe given
,j ust to help on the process of mixing
,and
to bring the stronger alcohol into contact with thespecimens .
3 56 PRESERVATION OF MARINE ORGANISMSFormol-Alcohol (Formalin Spirit) . -This is made by
adding 5 per cent . of commercial formol (40 per cent .
formaldehyde) to alcohol of 70per cent thus Alcohol
70 per cent . , 95 c .c . formaldehyde 40 per cent 5 c .c .
Formol-alcohol is one of the best preserving fluidsfor general collections which are not required forhistological work . The specimens are put directlyinto the fluid, which should be changed after abouttwenty- four hours . In the case of animals whichcontract readily, they Should be anaesthetized withcocaine , menthol , or weak spirit , before being put intothe formol- spirit .In cases where it is important to preserve delicate
calcareous structures Holothurians) this mixturei s ri ot recommended ,
as it may develop an acid re
action .
B . FIXING FLUIDS .
Corrosive sublimate (bichloride of mercury,Hg.Cl, )
is probably the most generally useful fixing fluid,when
specimens are required for minute study of their cellstructure .
It is used either as a simple saturated solution In
water,or can be mixed with glacial acetic acid if it
is not desired to preserve calcareous structures . Formarine animals the following proportions are recom
mended Bichloride Of mercury,saturated solution in
distilled water,
*95 c .c . ; glacial acetic acid , 5 c .c .
Both the Simple saturated solution of sublimate and
On e hundred cubic centim etres of d istilled water will dissolve 6 or 7 gramm es of bichlor ide of m ercury at ord inarytem p eratures . It is best to add an excess of the bichlor ideand dissolve in hot water . On board ship it is easiest to have a
b igbottle ,with an in ch or two of p owdered corrosive sublim ate
at the bottom , and fill it up with water every n ight it will besaturated by m orn ing if shaken oc casion ally .
3 58 PRESERVATION OF MARINE ORGANISMSsimilar to that described above
,excepting that after
using the sea water solution the washing in fresh watershould be more thorough .
This is a most deadly poison if taken internally, anda saturated solution looks exactly like plain water.
Picric acid is a bright yellowish flaky powder,which
is scheduled under the Explosives Act . In a glassbottle by itself there is good evidence that it is aharmless substance
,especially when kept under water
,
but on the discharge near it of a detonator it becomesa violent explosive . It is used in the manufacture ofbombs and shells
,under the names of melinite
,lyddite
,
etc . The Board of Trade Regulations forbid its conveyance on board a ship (see p . 1 1 1 ,
note ) .Picric acid is often used for rapidly killing marine
animals,and is a good fixative
,with a great penetrating
power . It may be either used alone or in combination with other chemicals . AS a saturated solution inwater is always used
,there is no trouble about making
up the stock solution . Simply place some picric acidin a bottle and fill up with water . If clean fresh watershould not be available
,then sea water m ay be used
instead . A little picric goes a long way , for one partof picric dissolves in about eighty- six parts of waterbut it is more soluble in hot water .There is one disadvantage with picric acid—namely,
the trouble of removing the yellow stain . After thespecimen has been properly fixed in picric , transfer itto alcohol
,and change the alcohol several times , until
the fluid is no longer yellow . I t does not matter very .
much about the specimen remaining yellow . To re
move all traces of the stain from the specimen generallytakes several days and many changes of alcohol .
SPECIAL FIXATIVES 3 59
Specimens , after they have been fixed with picric,
Should not be soaked in water ; but if they are notwanted for histological work
,then formalin may be
used instead of alcohol .
Picro-formol Solution.—This so lution is a sp lendid fixativewith a great p ower of p en etration , and kills very qu ickly .
B ou in ’
s form u laP icric ac id
,saturated aqueous so lution , 75 p arts form alin
30 or 40 p er cent .,25 p arts acetic ac id
, 5 p arts .
When fixation is comp leted wash ou t the stain with alcoho l ,and preserve in 70 p er cen t . alcoho l . I f the spec im en s shou ldn ot be wan ted for h istological work , then form alin m ay be
u sed in stead of alcoho l .Chromic Acid.
—Weak solution s of chrom ic ac id in waterare often u se fu l ; 2 p er cent .
,1 p er cent and o 5 p er cent .
solution s are gen erally em p loyed , the sp ec im en s rem ain ing inthe solution for som e hours . A fter chrom ic ac id the sp ec im en s Shou ld be very thoroughly washed in fresh water ,
be ingallowed to rem ain in runn ingwater for even twen ty-four hours .
A fter washing they are tran sferred to 30 p er cent . alcoho l,
then to 50 p er cen t . alcohol , and finally to 70 p er cen t . alcohol ,in which they m ay be kept . Chrom ic ac id sp ec im en s are bestkep t in the dark .The d isadvan tage of chrom ic ac id is that obj ects p reserved
in it are Often d ifficu lt to stain .
Chromo-acetic Acid.- Chrom ic ac id ,
02 to 0-25 p er cent ;
acetic ac id O‘
I p er cen t .,in water . Proceed as in the case of
chrom ic acrd .
Flemming’
s Fluid (Strong) . One p er cen t . chrom ic ac id1 5 parts 2 per cent . osm ic ac id , 4 parts glac ial acetic ac idI p art .
This is on e of the best fixing agen ts for p reserving the
m inute structure of cells . On ly sm all p ieces of tissue shou ldbe put into th is flu id
, as it does not p en etrate we ll . The
spec im ens shou ld rem ain in the flu id for several hours , or ifthey are large for several days . Wash we ll in runn ingwater ,
as
in the case of chrom ic ac id spec im en s , and br ing gradually to70 p er cent . alcoho l .The sp ec im en s are gen erally very m u ch blacken ed by the
osm ic ac id in the solution ,and are o ften d ifficu lt to stain ,
espec ially if the washing has not been sufii c ien tly thorough .
366 PRESERVATION OF MARINE ORGANISMSHermann
’
s Solution .—This is sim ilar to F lemm ing’
s so lution ,
excep ting that 1 per cen t . p latinum chlor ide is u sed in steadof 1 p er cent . chrom ic ac id . The solution is u sed in the sam e
way as F lemm ing’
s solution . It is said to p reserve the protop lasm ic stru ctures better than Flemm ing’
s flu id .
Osmic Acid.—A very p ower fu l killing agent for sm all
organ ism s,such as Protozoa or sm all Cru stacea . It is gen erally
used in 5 per c en t . solution . The vap our of the ac id is alsou sed , a drop of water con tain ing m inute organ ism s be ing putin a c losed dish in which a few drop s of osm ic ac id solutionhave been p laced . A great disadvan tage of osm ic ac id is
that it blacken s the sp ec im en very m uch,espec ially if the
tissue is of a fatty n ature ; the blacken ing can be rem ovedwith a weak solution of chlor in e ,
which does n ot im prove thetissues for m icroscop ic work .
C. ANzE STHETICS .
I f put imm ediately into a fixing flu id m any m ar ine an imalscon tract and shr ink up . It is there fore n ecessary , in order to
get we ll—exp anded sp ec imen s , to ana sthetize before killing.
The substan ces generally u sed for this purpose are cocain e ,
m enthol , and very weak alcoho l . Chloral hydrate is alsosom etim es used
, as well as other anaesthetics . It is to be
n oted ,however , that the m ethods of anaesthetization are n ot
to be recomm ended for u se in the trop ics the an im als die and
rot too qu ickly in sm all bodies of water (see p .
Cocaine (hydrochloride of c ocain e) is a usefu l and p ower fu lanaesthetic . A 1 p er cent . so lution in distilled water Shou ldbe m ade up and a few drop s added to the sea water contain ingthe living sp ec im en in a fu lly exp anded condition . It is bestto in crease the dose at intervals , and n ot to add the fu llqu an tity at on ce or sudden ly . A sudden overdose frequ en tlym akes the an im al con tr act ; if it does n ot Show sign s of ex
p andingwithin about thr ee m inutes , then rem ove it in to a vesselof c lean sea water and let it revive . Try n ext tim e with lesscocaine .
Solution s of c ocain e do n ot keep very long, and are usuallyspoilt by fungo id growths . It is advisable n ot to m ake upm ore than 100 c .c .
D irectly the an im al becom es anaesthetized p our in the
killing or fixing solution . A fter adding corrosive sublim ate or
p icr ic ac id a prec ip itate is frequ en tly produced . The pre
362 PRESERVATION OF MARINE ORGAN ISMS
put in . Even then it is liable to slip up,especially if
the tube contains alcohol . There is always an un
certainty with corked bottles . They are safe for Shortperiods up to about twelve months
,and after that
they should be examined at least once a year . Therisk of leakage and evaporation can be considerablyreduced by coating the cork with paraffin wax,
andthis should always be done before finally storing awaythe bottles . The method is quick and simple
,and
the gain in security is well worth the trouble . It is asfollowsAfter corking , wipe the top of the cork and the rim
of the bottle , and then place the bottle aside for aday , or longer , to dry . It is very important that thecork Should be perfectly dry , and no fluid in thecrevice between the rim and the cork . When thebottles are ready for coating , melt some hard p araflinwax (paraffin wax candles or any kind of hard waxm ay be used) in a small metal pot . A gluepot is agreat comfort for this purpose on board ship it canbe stood on the galley- range . Then dip the corkdeep enough to cover about a quarter of an inch ofthe glass . After the first coat has solidified andcooled
,give a second dip
,quickly in and out , or else
the first coat will have time to melt off. A bottle ortube properly sealed with paraffin wax will standagainst evaporation for several years . Some bottlesand tubes recently examined after being stored awayfor eight years were quite sound but a few showed aSlight loss of fluid
,though the paraffin coating was
externally flawless and perfect . On further examination it was found that the paraffin was no longeradhering to the glass .
Miniature bottles, with a capacity of about i“ ounce
(1 5 made of thin glass and fitted with a good
STORAGE BOTTLES
cork,are very useful and convenient for small speci
mens . All bottles should have wide mouths , and the1 ounce (30 2 ounce , 3 ounce , and 4 ounce Sizesare recommended .
Some wide-mouthed bottles are sold with a corkfastened on to a wooden cap . They look very neatand nice
,but have proved to be an utter failure for
fluids .
Alcohol dissolves out the brown tannin in cork , andthe specimens usually absorb the tannin , and turn toa brownish colour . If the specimens are wanted forhistological work
,corks should be avoided and glass
stoppers used .
Bottles with Glass Stoppers .-For the permanent
storage of specimens a glass- stoppered bottle is notto be surpassed . The small sizes—1
5 ounce (1 5 c . c . ) to
4 ounces (1 20 c .c . )—are most suitable for general use ,
and when larger sizes are required it is much cheaperto select a good glass- capped fruit- j ar .Glass- stoppered bottles vary considerably in quality
and in price . The cheap ones have rather coarselyground stoppers
,not always fitting accurately in the
neck of the bottle . The best quality have verysmooth- ground stoppers
,each ground to its bottle ;
they fit accurately,and are usually numbered .
Everyone who has had any experience with glassstoppered bottles sooner or later finds out that eventhe best quality bottle is not absolutely proof againstthe evaporation of alcohol . To prevent evaporationthe stopper is often coated with vaseline or lard . Thedisadvantage of vaseline is that it becomes too liquidin warm weather
,and it gradually works its way down
the stopper and drops into the fluid,forming a harm
less oil globule in alcohol,and an Oily scum over
formalin . Lard,on the contrary
,slowly loses its
364 PRESERVATION OF MARINE ORGANISMSgreasy nature and dries up . A mixture of vaselineand beeswax is perhaps the best substance for glassstoppers . It is made by first melting in a pot a fewsmall lumps of beeswax
,adding some vaseline
,and
well stirring up . The consistence of the mixture,when
cold , should be like soft butter on a warm day . Thebeeswax raises the liquefying-point of vaseline . Thewhole of the ground glass of the stopper should notbe coated with the mixture
,but only the uppermost
part . Just put on a narrow band with the aid of apenknife or a flat stick .
When glass- stoppered bottles containing specimensare sent by post or by train
,the stoppers Should be
tied down with string or held by a rubber band .
Glass JarswithMetal Caps.—These j ars are commonly
sold for the storage of j am,honey
,and other sub
stances . Their Sizes are denoted by their capacity forweight
,and not by fluid capacity . The most useful sizes
are the 3 pound (holding 5 fluid ounces,or 1 50 c . c . )
and the 1 pound (3 50 The metal cap screws onto the rim of the j ar
,and inside the cap there is a
thin sheet of common cork , which is quite satisfactoryfor jam , etc .
,but not for fluids . The cap is sometimes
made of iron coated with tin or some other whitemetal
,or it may be made of a soft or hard alloy of
some kind or other . These j ars,as purchased , are
very useful just for temporary purposes , but notsuitable for a long storage of specimens . As the j arsare very cheap and very convenient , several attemptshave been made to render them watertight and to keepthe fluid away from the metal . Alcohol , and especiallyformalin , attacks the metal cap ,
and if left long enoughthe metal corrodes away and the cap becomes perforated . The most successful method for makingthese j ars serviceable is the one used in the laboratory
366 PRESERVATION OF MARINE ORGAN ISMSstead of a cork , and they are at once placed into awide-mouthed glass j ar , filled with the same fluid as
in the tubes . It is an excellent system for collectingexpeditions , as the small tubes are safe inside thelarge j ars , and are quickly packed . It is advisable toplace a layer of wool at the bottom of the jar , a littlebetween the tubes , and some on the top . This willprevent the tubes from rattling about inside the jar ,and reduce the risk of breakage . The large jar mustbe filled to the brim with fluid
, so that all the tubes areproperly immersed .
Damage done by Air Bubbles in Tubes and Bottles.
Although great care is sometimes taken in preservingspecimens , yet no care is taken in properly storingthem for travelling . There is nothing more disastrousto delicate animals than an air bubble rolling up and
down a narrow tube,
‘
or a large air- space in a bottlewhich is subj ect to the rolling of a ship or the shakingof a railway train . There is not the slightest difficultyin filling a bottle with fluid up to the bottom of thestopper , but narrow glass tubes require special treatment . Fill the tube to the brim with the preservingfluid
,and insert a tight -fitting plug of absorbent
cotton-wool,which Should have been previously soaked
in the same fluid . After a little practice it is quiteeasy to insert the plug without introducing an air
bubble . The tubes can either be stored in a largeglass jar , filled with the preserving fluid , or corkedand sealed with paraffin wax.
Labels.—Those who are contemplating an extensive
collecting expedition should provide themselves withproper labels
,made of good paper , upon which , at least ,
Should be printed : Date,
” Number ,”
Locality ,
”
Preservation . The best and safest place for a labelis no doubt inside the bottle
,and as the label will be in
PLANKTON 367
the fluid , it is necessary to select a tough ,unglazed paper
(see p : A record which is frequently omitted onlabels is the method of preservation . It is by no meansan unimportant detail
,especially when the specimens
are handed over to a specialist for examination .
I I I . PRESERVATION .
Plankton .—The preservation of the whole catch of
a tow net,j ust as it comes on board , without any
sorting of the specimens,is a simple operation .
Animals with hard coats,such as Crustacea , stand the
treatment very well,but soft-bodied animals , such as
j elly-fishes,usually contract and become very much
distorted .
The best method is to pour the Plankton from thecan (at the bottom of the tow net) into a glass j ar .
Stir the Plankton round with a rod,and at the same
time pour in a little formalin 5 per cent . or 10 percent . Take out the larger animals with lifter and
pipette . Keep on stirring for about a minute , so asto mix thoroughly the formalin with the sea water ;then allow the Plankton to settle to the bottom .
Soon after the Plankton has settled,pour off as much
of the fluid as possible,and transfer the Plankton to a
bottle . Allow the Plankton to settle , and reduce thequantity of fluid to a minimum . The next step is tofill up the bottle with formalin 5 per cent . or 10 percent . , and occasionally give the contents of the bottlea stir up . A bottle should not be more than half fullof Plankton . It is advisable after a few days eitherto pour off the formalin and add a fresh supply ,
or topour in a very small quantity of strong formalin .
Opalescence of the fluid is a Sign that it needs changing .
368 PRESERVATION OF MARINE ORGAN ISMSAnother method is to first kill the Plankton by
pouring some picric acid solution into the glass jar ,and then add a little formalin 5 per cent . or 10 percent . Leave the Plankton in this very dilute p icroformol solution for an hour or two
,occasionally stirring
up . Finally transfer the Plankton to a bottle,and
fill it up with formalin 5 per cent . or 10per cent . Thefluid will remain yellow , but the small quantity ofpicric present may be neglected . It is important touse plenty of formalin , for an extra strong dose doesno harm ,
and to remember occasionally to stir up thecontents of the bottle .
Corrosive sublimate must never be used instead ofpicric acid for this wholesale method of quickly preserving Plankton . The presence oi corrosive sublimatein formalin leads to the formation of a precipitate
,
which adheres firmly to all the specimens .
Protozoa may be preserved in weak osmic acid . Ifthey are numerous , the osmic acid m ay be added tothe water containing them (2 or 3 drops of 7
3; per cent .
osmic to 10 c .c . of water) the Protozoa are allowed tosettle
,or
,better
,separated by means of a centrifuge .
They should be stained with dilute pioro - carmine,and
brought gradually into 70 per cent . alcohol .If one is dealing with a few specimens only in a drop
of water on a slide , the drop may either be exposedto osmic acid vapour, or some solution may be runin under a cover-glass .
Radiolaria Should be preserved with dilute osmic
acid ,or with corrosive sublimate . Acanthom etra killed
with corrosive sublimate (about one minute in saturatedsolution) keep better than those preserved in osmic acid .
Porifera.—One Simple and ready method of pre
serving sponges satisfactorily is to hang them up instrong alcohol (the strongest obtainable , absolute
3 76 PRESERVATION OF MARINE ORGANISMSdepends to a great extent upon the healthy conditionof the specimens . D irectly the tow net comes onboard
,the Plankton must be poured into a glass j ar
,
and the j elly-fishes at once picked out by means ofa pipette or some other handy instrument
,and p laced
in a glass vessel containing sea water . This glassvessel must be absolutely clean ,
and free from theslightest trace of chemicals .
The medusae Should be given about half an hour toexpand and to recover from the Shock . If the medusaeafter the first half-hour look in a sickly condition
,the
sooner they are preserved the better but if in a healthycondition there is no need to hurry over their preservation . They m ay be left in the vessel for severalhours
,provided that it is kept in a cool place out of
the heat of a summer’s sun .
The simplest and quickest method for preservingeither a few specimens or several dozen is by pouringdiluted formalin into the sea water . The secret ofsuccess depends upon keeping the medusae in motionwhilst the formalin is being poured in . First stir themedusae very Slowly and very gently round and roundwith a clean glass rod . When all are in motion
,begin
pouring in the formalin Slowly and gently down theSide of the vessel . About 10 c .c . of formalin 10 percent . m ay be taken as about the mean quantity to addto 100 c .c . of sea water . An exact quantity is of littleimportance , and it is better to add too much than toolittle . Keep the medusae in motion whilst the formalinis being added ,
and for at least two minutes after .
The stirring is very important , as it produces an evendistribution of the formalin in the sea water, and
the motion keeps the medusae off the bottom , andallows them to die in a fairly well- expanded condition . Some species are more liable to contract than
JELLY-F ISH 37 1
others,and much depends upon the condition of the
specimens .The medusae may be left at the bottom of the vessel
for a few hours , and then they should be transferredto a stronger solution of formalin—about 5 per cent .
and finally stored away in formalin 10 per cent .
To obtain medusae in a nice state of expansion,and
with tentacles stretched out , it is necessary to use an
anaesthetic . This gives a little extra trouble,but the
results are well worth the trouble when really nicespecimens are wanted . One of the best anaesthetic sis hydrochloride of cocaine , in either a 1 per cent . ora 2 per cent . solution .
Place the medusae in a smal l glass vessel with j ustsufficient sea water for them to swim in . After theyhave expanded , add a little cocaine (about 3 c . c . of1 per cent . for every 100 c . c . of sea water) , and stirgently with a glass rod to mix the cocaine with thesea water . If the medusae at the end of about tento fifteen minutes have their tentacles expanded
,and
do not contract when touched with a glass rod,no
more cocaine need be added ; but if still active , adda little more cocaine , and repeat the stirring process .
I t is better to add about half the cocaine at first,and
gradually to increase the quantity , than to give thewhole dose at once . An overdose generally causes aprolonged contraction .
‘
AS soon as the medusae areanaesthetized , stir them gently round and pour in theformalin solution . Keep on stirring whilst the formalin is being added , and for a minute or longer after .
Specimens must not be left long in any solutions containing cocaine
,as it has a softening action upon the
j elly . A medusa anaesthetized with cocaine may alsobe killed with picric acid , corrosive sublimate , or anyother good fixing solution .
372 PRESERVATION OF MARINE ORGANISMSSiphonophores.
—The belled forms (Calycon ectae) areabout the easiest siphonophores to preserve
,and for
them formalin is recommended . The stolon bearingthe cormidia usually becomes contracted
,but occa
sionally one is killed in an expanded condition . A
sudden dose of picric acid is a good killing agent,as
it acts very quickly . Leave the specimens in thepicric for about twenty minutes, and then graduallytransfer to formalin or alcohol .The forms with a small float (Physonectae) require
a considerable amount of Skill , patience , and ex
p erience for their successful preservation in an ex
panded condition . Unless one is prepared to devotethe necessary time and attention to the Operation
,it
is far better to place the colonies of these and the othergroups in formalin 5 per cent . or 10 per cent and
chance the result . When dismemberment of thecolony takes place , collect the fragments and put themall into a small bottle .
For killing colonies in an expanded condition a
mixture of corrosive sublimate and copper sulphateis frequently used . After the death of the colony
,a
few drops Of nitric acid are added to prevent theformation of precipitates . Then Flemming ’s solutionis poured in for the purp ose
'
of hardening the tissues .
After about twenty- four hours in the above mixturealcohol is introduced , j ust a few drops at a time , andthe strength very slowly and gradual ly increased to
70 per cent . Nearly all the methods for the p reservation of Siphonophora were published before the adventof formal in ,
and alcohol is always recommended .
Formal in ,however, has several advantages over alcohol
for these delicate organisms , and should always begiven a good trial .Menthol has been used as an anaesthetic with some
374 PRESERVATION OF MARINE ORGANISMSIt is a distinct advantage , soon after killing the
medusa in formalin , to pour in some chromic acidabout a 5 per cent . solution—j ust enough to colourthe formalin . The chromic acid makes the j elly toughand more pliable , so that there is less risk of breakagewhen the specimens are handled for examination . Theyellowish-brown colour of the chromic acid may bedisregarded , because in the course of a few months thecolour changes to a pale bluish- green
,owing to the
oxidation of the chromic acid .
The successful preservation of Scyphomedusae ,especially the large ones
,greatly depends upon using
plenty of strong formalin .
Ctenophores are troublesome animals to preserve ,because nearly every genus requires special treatment .There is , however , one general rule to be rememberednamely , that Ctenophores must not be stored away informalin , but always in alcohol 70 per cent .
Pleurobrachia m ay be killed in formalin 5 per cent .
in sea water . The simplest method is to fill a largetest- tube or a tall cylindrical measuring-glass with theformalin solution
,and to
_
drop the specimens in . Leavethem alone until they sink to the bottom , and thenremove to formalin 5 per cent . in fresh water . Theymay be left in formalin for a few weeks , but it is bestnot to delay their transference into alcohol too long .
Begin with very dilute alcohol , and gradually work upto 70 per cent . strength .
Beroe m ay occasionally be killed in a fairly good ,expanded condition by allowing it to swim in a smallglass pot
,with just sufficient sea water to cover it ,
and then ,when fully expanded ,
pouring in very quicklya large quantity of corrosive sublimate (saturatedsolution in sea water) . As soon as the specimen hasbecome white
,pour off the corrosive and add fresh
ANEMONES, CORALS, STARFISH 3 75
water . Wash it well in several changes of water toremove the corrosive , and then transfer gradually fromvery weak alcohol to 70 per cent . alcohol .Bolina dissolves up at once in formalin . The best
results are obtained by killing quickly with Flemming
’
s solution , and selecting quite small specimens .Leave them in the solution for about half an hour ,wash slightly in water , and transfer very graduallyfrom very weak alcohol to 70 per cent . alcohol .Flemming
’
s solution is about the best killing andfixing solution for Ctenophores .
Anemones and Corals are amongst the most difficultof marine animals to preserve in an expanded state .
For ordinary sea anemones,formalin ,
followed byformalin—spirit , is preferred . The method which ismost often successful is to anaesthetize with menthol
(p . the process usually takes from twelve totwenty- four hours . When the creatures no longerreact when touched , plunge them suddenly into formalin or formalin- spirit (see p . or into hotcorrosive sublimate
,any one of which preserving fluids
gives good results .
For corals ,” such as Caryophyllia,
Alcyonium ,and
Gorgonia , use hot corrosive sublimate after the menthol ,or 5 per cent . formalin followed by cold saturatedcorrosive sublimate . But a plunge into 90 per cent .
spirit , not allowed to get weaker than 70 per cent . ,
has given fair results for anatomical work .
Starfishes.
—Specimens required to show only externalfeatures may be preserved in 70 per cent . alcoholor in formalin . They retain their natural shape betterif they are put for two or three minutes into freshwater before being placed in the preserving fluid . Ifthe internal anatomy is to be studied , an incision shouldbe made along the length of each arm , so as to allow
3 76 PRESERVATION OF MARINE ORGANISMSthe preserving fluid to enter
,and the specimen be
preserved in 2 per cent . chromic acid,washed in run
ning water, and transferred to 70 per cent . alcohol ;or the specimen may be placed at once in formalinspirit , or 5 per cent . formalin , without the use ofchromic acid .
Antedon .—Specimens thrown flat into a shallow
dish of strong spirit give good results . There shouldbe j ust enough spirit to cover the specimens .
Echinoids.-Echinus and similar forms may be pre
served with the tube feet expanded by transferring aheal thy specimen suddenly to strong acetic acid or towarm 70 per cent . alcohol . If only the internal partsare required, a hole should be made in the shell , andthe specimen put at once into 70 per cent . spirit
,or
into formalin- spirit .
Holothurians—Specimens merely killed In spirit , andwith spirit also inj ected by the anus , are sufficient forthe purposes of the ordinary collector .
Formalin and all acids Should be avoided , as it isimportant not to inj ure the calcareous plates in theskin .
But if nicely expanded‘
sp ecim en s are desired, theyshould be ana sthetized in the ordinary way withmenthol (about twelve hours) . They will then generally remain expanded . As soon as they cease toreact when the tentacles are touched , they m ay betransferred to 70 per cent . spirit , and at the same timeinj ected with 90 per cent . Spirit through the anus .
Polychae ta.—To preserve these worms the following
has proved to be the most useful general method Theworms are first placed in a vessel of clean sea water ,and 70 per cent . alcohol is added drop by drop , and
mixed by gentle stirring with the sea water . Theoperation is repeated every few minutes, the dose of
3 78 PRESERVATION OF MARINE ORGAN ISMSinstead of formalin- spirit . For their further treatment , see p . 3 59 .
We are indebted to Mr . R . T . Leiper for the following notes on the preservation of parasitic worms .
(a) Preservation .
Nematoda.—The worm s are washed by shaking in I p er cent .
saline solution , killed by p lunging each separate ly into a
quantity of 70 p er cent . alcohol that has been heated to its
boiling-
p o in t, and stored in fresh 70 p er cent . alcohol forexam ination . I f this m ethod is p rop er ly app lied the worm s
shou ld die in an extended and straighten ed position .
Trematoda.—Clean by shaking in a test-tube half fu ll of
1 p er cent . saline so lution ; the d irty liqu id havingbeen decantedOff
, one-third of the tube is filled again with 1 p er cen t . sal ine ,
in
which the worm s are shaken vigorously , and an equal quan tityof saturated HgCl2 qu ickly added—the vigorous shaking beingcontinued for several m inutes thereafter . This treatm en t
shou ld kill and fix the flukes in an extended p osition . The
p arasites m ay be left in the fixing flu id several days , or theym ay be tran sferred imm ediate ly to water ,
washed for twe lvehours
,and fin ally stored in 70 p er cen t . alcohol .
Large trem atodes , section s ofwh ich are requ ired for d iagnosis ,
m ay be treated in the sam e way ,or form alin 10 p er cent . m ay
b e substituted for the corrosive sublim ate as fixing reagen t,
and a weaker strength , say 3 p er cen t .,u sed as a stor ing
m ed ium .
Cestoda.—The strobila are washed gently in 1 p er cent .
salin e,fixed in a solution con tain ing equal p arts of saturated
corros ive sublim ate and 70 p er c en t . alc oho l , to wh ich a few
drop s of glac ial acetic ac id have been added—the whole heatedto about 50°
C . The tap eworm s rem ain in the fixingflu id untilit is co ld they are then washed in run n ing water for twe lvehours , and tran sferred to 70 p er cent . alcohol .
(b) Examination .
Nematoda.—The worm s , p reserved in 70 p er cent . alcohol .
are tran sferred to a solution m ade up of 70 p er cen t . alcoholcontain ing 5 p er cen t . glycer in e . This solution is then p lacedon a warm p late or in cubator at about 60° C .
,and allowed to
evap orate slowly . The process takes about twen ty- fou r
WORMS , CRUSTACEA 3 79
hours,or even two days , to com p lete ,
by which tim e the alcoho lan d water will have p assed off as vap our ,
leaving the worm s
in visc id—alm ost p ure—glycer in e . They m ay then be exam
in ed in pure glycer in e ,or m oun ted in glycer ine j elly as per
m an en t slide -
preparation s .
For rap id exam in ation the Sp ec im en s after fixation in
bo il ing 70 p er c en t . m ay b e tran sferr ed to abso lute a lcoho lfor thirty m inutes , and then c lean ed in white creosote .
B y this m ethod the details of all sm all n em atodes m ay b e
seen p er fectly . In the case of large form s,l ike som e of the
A scar idae , the details of intern al an atom y c an be m ade out bytran sferen ce from 70 p er cen t . alcoho l to Sp ir it , an d then ce tocreosote . The worm s shou ld be exam in ed in creosote ,
and
then return ed ,for keep ing, to 70 p er cent . alcoho l .
Trematoda.—Sm all form s are exam in ed who le , after c lear ing
in creosote ,be ing tran sferred thereto from sp ir it .
For exam ination of large Opaque form s section s are n eces
sary for this rap id transferen ce from form alin through aceton e
dir ect to paraffin is su itable .
When dehydration is com p lete ,which m ay b e tested by
transferen ce to an ilin e oil (if th is is don e the sp ec im en m u st
be return ed to aceton e ) , tran sfer to a warm m ixture of aceton e
and p araffin , when infiltration is rap idly effected under an
exhau st pum p .
I f it is des ired to stain whole flukes they shou ld be le ftseveral days in very weak haem atoxyl in , and then differentiatedwith weak ac id .
Cestoda.—Stain by imm ersion in weak haem atoxylin after
fixing, or by d ir ect imm ers ion whilst alive in weak haem atoxylinand weak glycer in e . D ifferen tiate with ac id after severaldays , and m oun t accord ing to general m ethods .
Copepoda, Ostracoda, etc .—Preserve in 5 per cent .
formalin in sea water . They may either be keptpermanently in this fluid , or be subsequently transferred to 70 per cent . alcohol , the latter being perhapsthe better plan .
For histological work , Hermann’s fluid or corrosive
sublimate give good results .
Amphipoda and Isopoda, Cirrhipedia, etc .
—Forgeneral purposes these may all be put directly into
380 PRESERVATION OF MARINE ORGANISMS
70per cent . alcohol . Formalin 5 per cent . may also beused , but it does not give such good results , as itattacks the carapace .
Decapoda—Crabs , shrimps , prawns , etc should be
killed in fresh water , and then put into 70 per cent .
alcohol. If put directly into alcohol,most of the
crabs are liable to throw off some of their legs . In thecase of crabs and lobsters larger than (say ) half acrown , it is advisable to slit up the membrane at theback of the carapace with a sharp knife
,so as to let the
alcohol get into the interior .
For histological work on all Crustacea any of theordinary preserving fluids may be used
,but they do
not easily penetrate the chitinous coat . Hot corrosivesublimate probably gives the best result . Excellentresults m ay , however , be obtained with Flemming
’s,
Hermann’s , and other fluids , if a specimen can be
obtained which has only j ust moulted and is in thesoft condition . The great secret of obtaining goodhistological preparations of Crustacea is to use onlyspecimens in this condition
,as not only is the preserva
tion very much improved,but the making of sections
becomes easy , instead of wellnigh impossible .
Polyzoa.—For general purposes Polyzoa are best put
directly into 70 per cent . alcohol . This enables thesoft parts to be examined , or admits of the specimensbeing easily dried for examination of the calcareousskeleton . If it is wished to preserve the colour of acolony , it Should be washed with fresh water to re
move the salt,and then dried in the air , without the
use of Spirit .
Bowerbankia- like forms and Ctenostom es in generalmay be preserved in formalin .
If it is desired to preserve material with the polypites expanded ,
first anaesthetize with cocaine , and
382 PRESERVATION OF MARINE ORGANISMSin chains . Pour a large quantity of the mixture intothe vessel containing the Salps . Wash well in waterbefore transferring to alcohol or formal in .
Doliolum and other very small Salps m ay be killedby dropping them into picric acid
,but simple formalin
acts very well .Fishes .
—The best preservatives for fishes are
( 1 ) Five per cent . formalin (say 2 per cent . form alde
hyde) (2) 70 per cent . alcohol ; and (3 ) 70 per cent .
alcohol to which 5 per cent . formalin has been added .
For preserving for a Short time only there is littledoubt that 5 per cent . formalin is the best , as both theform and colour are better retained . After a considerable time , however , the specimens deteriorate .
Holt and Byrne recommend preserving first in 5 percent , formalin (40 per cent . strength) , and then transferring to alcohol
,or after a few weeks to equal parts
95 per cent . alcohol and formalin 5 per cent .
Fish intended specially for dissection are best preserved in formol - alcohol .The best way of preserving the colours of fish is to
preserve in 5 per cent . formalin , and keep the specimensin the dark . But ' even —under these conditions thecolours last a few months only .
Fish Eggs and LarVEB .
—These are best preserved in
5 per cent . formalin . They retain both form and sizewell in this fluid
,whereas in alcohol they Shrink con
siderably .
CHAPTER XII
WHALES, SEALS, AND SEA-SERPENTS
BY D’ARCY WENTWORTH THOMPSON
I . Whales.
THERE is a deal of interest in whales . The seafarerrej oices to meet them in the monotony of his oceanvoyage the fisherman welcomes them in the narrowwaters as harbingers of the herring—shoals ; the merchant sees in them the obj ect of a rich and still wideningcommerce ; the naturalist considers their manifoldvariety in form and habit , the marvellous adaptationof their bodies within and without to their strangeexistence
,their orderly migrations
,and the unsolved
problems of their remote ancestral origin .
Whales and dolphins of all kinds form ,in our modern
classification , the group Cetacea for so we have learntto use an ancient word which the Greek mariners usedof all manner of great sea-monsters
,shark or tunny
or whale . And the Cetacea form ,for us
,one order
of the mammals—that is to say, of those warmblooded vertebrate animals that suckle their youngat the breast . Behind these simple facts we hide adeal of ignorance ; for as to what the mammalia are
,
how their several orders are related to one anotherand in what way or ways they have been evolvedfrom Reptiles or other lower vertebrates , of all thesethings we have neither definite knowledge nor plausible
3 83
03 84 WHALES , SEALS , AND SEA- SERPENTSand accepted hypothesis . But whether or no
,the
Cetacea are mammals and not fish . The hairy coatof the ordinary mammal has disappeared ; for, wetand matted , without its entanglement of air , the hairycovering would wholly cease to act as an efficientnon-conductor of heat . Its part is played by thethick layer of blubber under the smooth skin
,and just
a few hairs remain about the lips , especially in theyoung
,to remind us of the former presence of a hairy
coat . The blood is copious and hot , and in variousparts of the creature ’s body complex networks of smallbloodvessels, the retia mirabilia , are formed tohold the plentiful supply . The hind- legs have disappeared to outer View ; but , within the body,
remnants of the pelvis , thigh-bones , and sometimes evenof the leg-bones
,are still to be found . The fore- limbs
are in many ways peculiar the arm-bone is extremelyshort
,sometimes almost as broad as it is long ; its
great round head moves freely on the shoulder-blade,
but elsewhere the limb has little or no freedom,the
fingers being bound together by sinew and skin,and
the flipper moving all of a piece . The flippers areusually small
,but sometimes of great length
,as in
the CaaingWhale (Globiocephalus) and the Humpback
(Megaptera) and it is not by their means that thecreature swims , but by the sculling action of the flukesof the mighty tail
,the flippers being in all probability
mainly for the purpose of maintaining equilibriumin the water
,for keeping the animal on an even keel .
While all other mammal s soever have in the fingersand toes the same number of j oints that we have , inthe whales these numbers are always exceeded ; andsometimes (Globiocephalus) the finger has twentyj oints or more
,so that the limb has a great resemblance
(however that may have been brought about) to the
386 WHALES , SEALS , AND SEA- SERPENTSthe Mystacoceti, which literally means the MoustacheWhales , but which name , more than two thousandyears ago ,
was already corrupted and punned upon into
p 89 7 6 Krj‘
ros,the Mouse Whale or Whal e Mouse .
There are two families of Whalebone Whales , theBalaenidae and the Balaenopteridae the former ihcluding the SO- called Right Whales , and the latterthe Rorquals or Finners and the HumpbackedWhale . The chief difference between the two familiesis one of degree
,the Whalebone in the former being
very long , and in the latter comparatively short .Naturally the mouth in the former is enormous
,and the
head also huge in proportion so that a very differentappearance is given to the animal
,and its body looks
Short and small behind its gigantic head . The RightWhales are by no means so large as the largest of theRorquals
,and 45 to 50 feet is a large size for a
Greenland Whale . Such a whale has Whalebone of1 1 to 1 2 feet in length ,
and Whalebone of 1 3 feet inlength is about the largest known
,at least nowadays .
Owing doubtless to the comparatively short body, theRight Whales have no dorsal fin ,
while such a finis always present (though sometimes small) in thelonger bodied Rorquals . Lastly
,and this is a useful
character for the recognition of the diverse kinds atsea
,the Rorquals disappear gradually from View,
seldom or never diving tail up,while the Right
’WhaleSdive more suddenly
,the great head plunging down
while the flukes of the tail are tossed upwards .
Among the Baleenidee many different Species ofBalaena , or Right Whale , have been described ,
and
naturalists are not yet agreed as to their number ordistinctive characters . In the North Atlantic regionwe have certainly two , Balaena mysticetus , the Greenland Whale , and B . glacialis or biscayen sis, the Bis
THE GREENLAND WHALE 3 87
cayanWhale , or Nordkap er , to which latter our whalingcaptains sometimes restrict the name Right Whale .
The Greenland Whale is the true Polar Whale , andis never found very far from the edge of the ice (Fig . 2 1 8)it is
,unfortunately , on the high road to extinction . In
the seventeenth century it was the obj ect of an immensefishery
,shared by Holland , England , and France
,
and the great Dutch settlement of Sm eerenberg,in
Spitzbergen ,employed at one time (about the year
1 680) 260 ships and over men . Those were thegreat days of the Arctic whale fishery . Oil was thegreat obj ect of the trade , for Whalebone was as yetof little value the cities of Europe were lighted withwhale- oil
,and the slaughter was prodigious . Before
long'
the whales became very scarce in the neighbourhood of Spitzbergen , where the Greenland Whaleappears to be now totally extinct ; it appears also tob e nowadays absent from the east side of Greenland
,
and it is not known from the north coast of Asia,
eastward of Spitzbergen , until we get very near toBehring Straits . The British whale fishers have at alltimes chiefly resorted to Davis Straits . Up to thebeginning of the last century almost every East Coastport S
‘
ent out its whalers , but at present about fourvessels from Dundee are all that is left of the dwindlingfleet . Between 1 788 and whales werebrought into Scottish harbours ; the present yearlyaverage is something like half a dozen . Another fleetof whalers still sails from San Francisco to the Sea ofOchotsk and the Behring Sea, and in summer- timethrough Behring Straits to Point Barrow and HerschelIsland . In 1 893 the fleet captured 293 whales . Somenaturalists are inclined to think that we have
,or had,
three great tribes or races of the Greenland Whale ,appertaining respectively to Spitzbergen
,to Davis
388 WHALES , SEALS , AND SEA- SERPENTSStraits and Baffin
’
s Bay ,and to the neighbourhood
of Behring Straits . It is in the last of these regionsthat the species seems still to exist in the greatestplenty . Much has been written about the annualmigrations of the whale , southward in autumn and
northward with the retreating ice . In the DavisStraits Fishery the old males come southward in earlywinter along the west coast of Greenland
,the females
and young animals taking a different course in thedirection of Hudson Straits . In spring the males gowestward from the neighbourhood of D isco
,and meet
the females somewhere about Baffin’
s Bay . Whenthe ice in Lancaster Sound breaks up
,the whales pass
northward ,and their chief haunt in summer is in the
neighbourhood of Prince Regent ’s Inlet .
The GreenlandWhale is deep bluish—black in colourover the back , and grey upon the belly ; the neck andthroat are white .
Long before the Arctic whale fishery began,a very
ancient and important fishery was carried on from theBasque cities . Of this fishery records are said to existas far back as the ninth century,
and when othernations began the pursuit of the whale it was Basquesailors who taught them the trade and accompaniedthem as harpooners . Harpoon itself is said to be aBasque word . This Basque fishery was very flourishingin the sixteenth century , and only became extinct inthe beginning of the eighteenth . We owe to the greatsurgeon
,Ambrose Paré, an account of the fishery at
its chief seat , Biarritz .
The BiscayanWhale differs from the Polar or Greenland Whale in several minor characters , but the chiefdifference is in the smaller head ,
and the correspondingly shorter Whalebone ; this does not exceed 7 feetin length
,and is of a coarser quality than that of the
3 90 WHALES,SEALS
,AND SEA- SERPENTS
GreenlandWhale . For a long time naturalists supposedthat this species was entirely extinct . In recent years
,
however, it has been captured in considerable numbersat several of the many whaling stations that have beenestablished on our own coasts and elsewhere around theNorth Atlantic . It appears to be not infrequent inIceland , and lately many examples have been got atthe whaling station of Bunavenader in the Hebrides .
This whale has also been got in the Mediterranean,and
it is known from as far Off as the Azores , Bermuda ,and Bear Island in the neighbourhood of Spitzbergen .
It is accordingly a great wanderer,and it may be that
its wanderings are greater still,for some naturalists
are inclined to doubt whether there be any real distinction between this species of the North Atlantic and theso—called B . australis of the Southern Ocean . Thislatter whale was the Obj ect of an immense Americanfishery in the beginning of the nineteenth century
,and
from 1 804 to 1 81 7 no less than southernRight Whales are said to have been taken by theirfleet . As in the North Atlantic
,this great Slaughter
was supposed to have led to its extermination,and
several Antarctic expeditions,including a small fleet
of Dundee whalers sent out in 1 892 ,have failed to
rediscover it . But it has been suggested that thereason for this failure is that the search has beenconducted in the neighbourhood of the ice , in placeswhere the GreenlandWhale would be likely to occurwhile
,on the other hand
,this southern whale was , if
not identical with,at least very closely akin to , the
BiscayanWhale , and lived remote from the ice in thetemperate regions of the ocean . In the northern halfOf the Pacific Ocean there is another Right Whale ,the so- called B . j aponica ,
hunted from time immemorial by the Japanese
,and in late years also by the
WHALES 3 91
Americans and the Russians . Its wanderings appearto be both wide and regular , from the Sea of Ochotskthrough the Kadiak Ground , off the Alaskan coastsouthward to Oregon . Scammon gives a vivid accountof the whale fishery in these seas . Here again thespecific distinctness of this whale is by no meanscertain
,and we may take it that it is at least very
closely akin to our Biscayan Whale . It is at all timesa difficult matter to identify with certainty the whalescaught by the whale fishers
,save in those cases where
the whales are flen sed ashore,under circumstances
where bones and other specimens are likely to becollected and preserved . Thus some of the Dundeewhaling captains are of opinion that any RightWhales which they occasionally get to the eastwardof Greenland belong
,not to the true Greenland Whale
or Bowhead,but to what they call the Right Whale ,
and we call the Biscayan Whale . Indeed,it is an open
question what species was the chief obj ect of the greatSpitzbergen fishery
,and I am inclined to think it is
not at all unlikely that the Atlantic or BiscayanWhaleformed a great part of the catch .
The family Mystacoceti contains one other speciesvery distinct from the rest this is the Pigmy Whale
(Neobalaena marginata) , a rare animal known only fromthe South Australian and New Z ealand seas . It isbut little known ,
and appears to be a link between thepresent family and the next it is only about 1 6 feetlong .
The Bala nOpteridte , including the Rorquals or FinnerWhales and a few others , are Whalebone Whales oflarge size
,resembling the former family in general
structure and habits,but with shorter Whalebone and
smaller heads ; there is a dorsal fin ,and the skin of
the throat is curiously pleated or furrowed in long
3 92 WHALES , SEALS , AND SEA- SERPENTSregular grooves . All the great whales that come ashorefrom time to time upon our coasts belong to thisfamily . A curious study of their occurrences on thecontinental coasts of the North Sea might be madein the seaport towns of Germany
, Holland ,and Den
mark , where it was for centuries the custom to recordthe stranding of a whale by a commemorative picturehung in the Rathhaus or Council Chamber . Till recentyears the whales of this family were immune frompersecution , but it is very different nowadays . Aboutforty years ago a Norwegian sea- captain
, Svend Foyn ,
began a fishery for these whales off the north coastof Finmark . The short baleen is of little value
,but
the whales yield an abundance of oil,their bones make
excellent manure,and even the flesh is utilized
,being
dried , ground to powder , and used in part for manureand in part for mixing with cattle- foods . Svend Foynmade a fortune
,and laid the foundations of a great
industry . Political reasons led towards the end ofthe nineteenth century to the closure of the Norwegianfishery
,the local fishermen asserting that the Slaughter
of the whales diminished their catch of fish ; but theNorwegian whale fishers c arried their trade elsewhereto Faeroe , Iceland ,
Scotland ,Newfoundland , and more
recently to a number of stations in the Southern Ocean ,
the Falklands,South Georgia , South Orkney,
and
elsewhere . In Shetland there are now four stations ,and there is another at Bunavenader , in Harris thereare also one or two in Ireland . The method of fishingis everywhere the same , by means of small steamersarmed with a powerful harpoon gun . The whales aretowed ashore , and their carcasses are rapidly disposedof with the aid of elaborate machinery .
The following table Shows the catch in Scotland inrecent years
394 WHALES , SEALS , AND SEA- SERPENTSThe industry is prosperous , and the demands for its
products appear to increase continually . It is certainthat it cannot long continue without making an impression on the numbers of the various species .
B . musculus , the Finner Whale , forms the bulk(68 per cent . ) of the Shetland catch . This is nearly ,
but not quite , the largest of the Rorquals , reaching a
length of over 70 feet . It feeds chiefly upon smallCrustacea , especially Calanus finm archicus . It is thecommonest of the Rorquals to be stranded upon ourshores . Closely allied to it is B . borealis
,or Rudolphi
’
s
Whale . This whale,which , till the establishment of
these whaling stations,was supposed to be exceedingly
rare , is now found to be abundant , but it is curiouslyirregular in its appearance . In some years—for instance , in 1 906
—it nearly equalled B . musculus in theShetland catch
,while in the previous year the latter
species was ten times the more numerous . The averagelength of this whale is a little over 40 feet . Its whalebone , though short , approaches that of the GreenlandWhale in fineness of texture , and is worth about £100a ton , or four times as much as that of the commonFinner .The greatest of all the Rorquals is B . sibbaldi—the
Blue Whale—whose average length is about 80 feet .This whale is rare at Shetland , but more abundantat Bunavenader ,
where,on the other hand , the
common Finner is less common than is the Shetlandone . The Blue Whale is also plentiful at Faeroeand Off the coast of Finmark it is likewise commonat Iceland and at Newfoundland and in the whalingstations of this latter island about 300 were caught inthe season of 1 904- 1 905 .
Allied to the Rorquals is the SO- called HumpbackWhale (Megaptera boops) , distinguished by its shorter
THE HUMPBACK 3 95
and bulkier form , and especially by its immenseflippers
,which are white in colour , and curiously
scolloped on the edge . This whale grows to a lengthof about 50 feet , and appears to be very widely distributed
,though it is not yet certain whether the
Humpbacks of the North and South Atlantic and ofthe North and South Pacific are distinguishable fromone another as species or races or not . AS a matter offact
,they are probably inseparable , but these whales
are particularly variable , and Captain Scammon declares that he never saw two alike . This is a truesurface- feeding whale , feeding in the North chiefly onBoreophausia,
and in the Antarctic on the largesouthern species of Euphausia but it does not disdainfish
,especially the Arctic Lodde (Osmerus arcticus) .
In the north it appears chiefly in summer- time , butalso sometimes in February and March . I t is said toswim quietly in summer- time , but to be very restlessin winter , when it approaches the coast for the purpose
, so the fishermen say , of freeing itself from parasites . It is certainly the case that this whale isespecially infested with barnacles
,and great clusters
of the large whale barnacle (Coronula balaenarum ) ,generally clustered over in their turn with Conchoderm a
aurita,are always to be found upon its skin . It is
said to be common about the Bermudas in February,
and in the Southern Hemisphere its chief abundanceis in the winter season so it may well be that this whalecrosses the line in its annual migrations . It is alsoone of the whales of which specimens caught on theEuropean coasts have been found with Americanharpoons embedded in them . This whale was reckoneda very rare wanderer to our coasts in former times
,the
great Tay whale of 1 883 being one of three or fourknown exam ples . But it is now caught regularly in
3 96 WHALES , SEALS , AND SEA- SERPENTSmoderate numbers both at Shetland and the Hebrides ,where together twelve individuals were killed in 1 909 .
In March,1 881 , it is recorded that the Varanger Fjord ,
in the North of Norway , was boiling with theseHumpback Whales .
On the Pacific Coast of America there is yet anotherlarge Whalebone whale , the Californian Grey Whale(Rachianectes glaucus) . This whale is , or has been ,
extremely abundant , chiefly off the coast of Californiaand Oregon , where it is hunted from the shore . It has ,however , a reputation for ferocity . In September ,1 908 , off the west coast of Vancouver Island
,I had
the good fortune to see a marvellous Shoal of whales,
in all probability of this species . The old “Amphion ,
”
under Captain (now Admiral) Frank Finnis , steamedslowly through them in a dead calm one Sunday morning , while service was being held upon the poop ,
andin every direction as far as one could see the greatbeasts were lolling and grunting and puffing and blowing on the smooth water .SO much for the family of Whalebone Whales , from
which we now pass to the Odontoceti, or toothedwhales . These entirely lack the Whalebone fringes , andare provided with teeth
,that vary greatly in number ,
disposition, and size . Typically (that is to say , in the
ordinary dolphins) , they are very numerous , small andconical—all alike , without distinction Ofmolars , canines,etc set in imperfectly formed sockets , or practicallyopen grooves
, along the edge of the jaw. There is buta Single set, no milk- teeth being displaced by thepermanent dentition . In Short , in a variety of waysthe teeth Of the dolphins are more like those of thereptiles than of the ordinary mammals .
The greatest of the toothed whales is the SpermWhale , or Cachalot (Physeter macrocephalus) , which
3 98 WHALES,SEALS
,AND SEA- SERPENTS
and Indian Oceans . But still earlier the Nantucketwhalers had pursued the SpermWhale , and the fisheryis at present entirely in American hands ; the readeris doubtless familiar with Mr . Frank Bullen ’s graphicdescriptions in The Cruise of the Cachalot .
’ Besidesthe Oil (which is much more valuable than that ofany other whales) and spermaceti , the Sperm Whaleyields the very curious product known as ambergris .
This is a concretion of the intestines,is usually inter
mixed with cuttle—fish beaks,and is probably a product
Of the digested cuttle-fish . It is one Of the mostcostly articles in commerce . While having but littleperfume of its own , it is a constituent of all the finerscents , and seems to have some curious property ofblending and improving the perfumes with which it ismixed . Now and then large masses of it have beenfound cast ashore or floating in the ocean .
There is a curious and rare species in the SouthernOcean , called the Pigmy Sperm Whale (Kogia) , aminiature—some 1 5 feet long—of its great ally .
There comes next a subfamily,known as the Ziphioid
or BeakedWhales . These are whales of moderate Size ,and
,like the Sperm Whale , make their diet of cuttle
fish . One species,the Bottle-nosed Whale (Fig . 2 1 9)
or Hyperoodon ,is the Obj ect of a fishery , chiefly in
Norwegian hands , and prosecuted by small vessels fromLabrador to Nova Zembla . The Bottle-nosed whalesgo about in small herds , and, like the other Ziphioids ,
the male and female are recognizably different , themale having greatly enlarged crests upon its skull .The Oil contains a considerable percentage of sperm aceti
,and the Skin makes an excellent leather , sup
plying a great deal of what are known as porpoiseleather boots . This whale can leap right out of thewater
,and is said to turn its head from side to side
DOLPH INS 3 99
while in the air .'
The other Ziphioids (Mesoplodon ,
B erardius , and Ziphius) are all more or less rare formswhich have been found in various parts of the world
,
but in such small numbers that the number andcharacter of the species are still in dispute . Meso
p lodon and Ziphius have both occurred on our owncoasts , and it appears to be a common or general rulethat when an individual comes ashore , its mate willbefore very long be found stranded in the near neighbourhood .
There remains the family of the Delphinidae , or DOI
phin s , which includes a number of very diverse forms .
The largest Is the Great Killer Whale , or Grampus
(Orca gladiator) , an animal reaching some 30 feet long .
This whale is easily recognized by its high curved dorsalfin . It has in each j aw ten or twelve powerful teeth .
Its body is conspicuously marked with white oryellowish bands . It is a fierce , predaceous creature ,attacking seals
,porpoises
,and the like , and even
sometimes the larger whales . Eschricht says thatthirteen porpoises and fourteen seals were taken fromthe stomach of a Single individual . Three species ofthe dolphin family are hunted by man . The first ofthese is the so- called Ca
’ ing Whale (Globiocephalusmelas) this whale is not large or valuable enough foran extended commerce
,but is of great value to the
inhabitants of Orkney and the Faeroe Islands , whereherds coming inshore in the summer months are surrounded by all the boats of the neighbourhood, anddriven with shouts and splashings to the beach . Thiswhale
,like the Sperm Whale , is a feeder upon cuttle
fish .
Next we have the White Whale , or Beluga (Delphinapterus leucas) . This is a northern species, especiallyabundant Off the coasts of Labrador and Canada ; it
46 6 WHALES , SEALS , AND SEA- SERPENTSis a small whale , about 10 or 1 2 feet long , and is aneater of fish, especially , i t is said ,
of salmon (Fig .
Its skin , like that of Hyperoodon ,is used for leather .
The Dundee whalers still bring a considerable numberOf White Whales , chiefly from
“
the neighbourhood ofCumberland Gulf .Closely akin to the Beluga is that very curious
creature , the Narwhal . The teeth of this whale are
all absent save one , and this one , which is present onlyin the males , is magnified into the long , twisted tusk
(Fig . In the embryo , besides rudiments of theother teeth , two small tusks m ay always be detected
,
and, as a rare abnormality , both o f these occasionallygrow to a full size . One such two -horned Narwhal , inthe museum at Hamburg , is one of the oldest naturalhistory specimens in the museums of the world . TheNarwhal is exclusively Arctic , but has now and thenwandered as far as our own coasts . It is valuable onlyfor its ivory , which brings a fair price . Some five- andtwenty years ago the price was extremely high ,
andI used to be told that the commodity had been cormered by a petty Indian raj ah , who stockadedhis palace all round with a fence of the tusks
,
confident in their exceptional Virtue against the EvilEye .
There is but little difference between the porpoisesand the true dolphins
,the chief being that the teeth
of the latter are pointed , while those of the former haveflattened ,
spade- shaped crowns . The porpoise is thecommonest of all our native Cetacea , and is Very irequently caught in the fisherm en
’
s nets . It comes farup our rivers
,and has been seen in the Seine at Paris .
Its flesh was an Old- time dainty , and , by the way, itis in this respect not exceptional , for the flesh of thelarger whales is said to be extremely good eating . I
46 2 WHALES , SEALS , AND SEA- SERPENTSseveral curious characters—among others
,a separation
of the cervical vertebrae , and consequent flexibility of
neck , which is found in no other Cetaceans . Thesethree genera constitute a separate family, the Platanistidm. The first of these is Platanista gangetica ,
theSusu of the Ganges it inhabits the Ganges and theIndus , going far up both rivers , and grubbing in themud for food with its long snout . The next genus
,
Inia , inhabits the Amazons its colour is in the mainpink , with many curious variations . It is said to bedangerous to m an ,
and the Sotalia ,already alluded to
,
is said to defend the swimmer against its attacks . Thelast genus
,Pon toporia ,
lives also in the rivers of SouthAmerica , especially the Amazons and the La Plate .
All of these fluviatile dolphins are rare in museums ,and the traveller should not neglect to take note oftheir habits
, and,when possible
,to preserve their
remains . I am told that there is one , for instance , inthe rivers of Sarawak
, Which does not appear to beknown to naturalists .
II . Seals.The seals
,or Pinnipedia
,constitute a suborder of
the great group Carnivora , .and agree with the landcarnivores in the main characters of their dentitionand in many other anatomical points . Awkward uponland , the seal
’s movements in the water are singularlygraceful . Swimming by means of its broad ,\ webbedfeet (for , unlike the Cetacea ,
the tail is Short and
degenerate) , aided by sinuous movements of the wholebody , the creature glides rapidly along , with nothingbut the head exposed ; and every now and then itstops to raise its little head and stare about with itsbig eyes .
TRUE SEALS 403
There are three fam ilies of seals : the Otarrrdae, orEared Seals ; the Trichechidae , or Walruses ; and thePhocidae , or True Seals . Of the Phocidae we have inthe North Atlantic region six species , all of which arecommon to both sides of the ocean , and of which allbut one have been found upon the British coasts .The common Grey or Harbour Seal (P . vitulina) , greywith darker spots , and with a black ring round the eye ,i s very common on our coasts , and has a bad reputationas a poacher of salmon . It is accordingly killed inlarge numbers at the mouth of the Tay and othersalmon rivers . I t swims far up into fresh water ; i tnever resorts to the ice , but breeds in rocky places onthe shore . It grows to about 5 feet long , or rathermore . A similar and probably identical species
,the
so - called Leopard Seal , i s found in California,and in
the North Pacific . I t has a close ally ,Phoca pallasii .
Smaller than the Grey Seal, and smallest , indeed ,of
the family,is the little Ringed Seal (P. foetida) , the
back of which is marked with large whitish spots .This seal is common in the Baltic , and is found nowand then on our own coasts , but its proper home is inthe Arctic . It is of importance to the Esquimaux forfood and clothing and it has curious habits makingfor itself roofed habitations in the ice , like the igloosof the Esquimaux . This is the
‘
seal whose bones areoften found in our Scotch brick- clays , which are ofglacial origin , and it must have been abundant onour coasts in that Arctic period . It is closely alliedto the Caspian Seal and to the seal which inhabitsLake Baikal and the presence of seals in these greatinland seas may perhaps be looked upon as a survivalfrom that same epoch . The Harp Seal , or GreenlandSeal , inhabits the edges of the drifting ice , and formsthe chief part of the great Newfoundland seal fishery .
464 WHALES , SEALS , AND SEA- SERPENTSThe adult male is whitish in colour
,with a great black
belt across the Shoulders and down each side, which
saddle- shaped mark only becomes fully formed aboutthefifth year . The female is much smaller the youngare pale grey , with dark spots . Still larger than theGreenland Seal is the Bearded Seal (Erignathus barbatus) , the Ogdook of the Esquimaux ,
which grows toa length of 9 or 10 feet . It is sometimes called theSquare-Flipper Seal . It is not uncommon in Norway .
On the other side of the Atlantic it goes as far southas Labrador , and is also found both in the Greenlandand the Siberian seas . The Grey Seal (Halichoerus
gryphus) is nowhere very abundant , but comes occasionally to our own coasts . It is confined to theAtlantic region . It is light grey in colour
,and the
male grows to 8 or 9 feet long . There is—or used inrecent years to be—a breeding-place of this seal onthe Fro Islands
,Off the Trondhjem Fj ord ,
where about100 young were reared annually
,and there are larger
breeding-places near Hammerfest but its numbers areof late years greatly diminished . Indeed , the habitof resorting , as this seal and the Greenland Seal do ,to a common breeding-fp lace , instead of going insolitary pairs , as the Common Seal does , would seemto be a sad disadvantage for the species in its strugglefor existence with mankind . The last of the northernseals is the Hooded Seal (Cystophora cristata) . Thisis a moderately large seal , the male being about 8 feetlong , and the female 7 feet . In colour it is bluishblack
,with whitish Spots ; but the young , as in the
Harp or Greenland Seal , are born white . The head issmall
, and bears in the male a very curious muscularsac
,which is capable of inflation , and when fully
stretched measures about 1 2 inches long by 9 incheshigh . This seal seems to be most abundant in the
466 WHALES , SEALS , AND SEA- SERPENTSseldom come under the observation of Europeantravellers .
In the Antarctic we have other species Of seals ,quite distinct from the northern genera . These are
Stenorhyn chus , the Leopard Seal , a very large speciesLobodon , the Crab - eating Seal Lep tonyx,
orWeddell ’sSeal and Omm atophoca,
or Ross ’s Seal , a small andrare species , with enormous eyes . Recent Antarcticexpeditions have added much to our knowledge ofthese seals, and have brought specimens in abundanceto our museums .
The last genus of the true seals is the Sea Elephant
(Macrorhinus) , of which one species (M. leon inus) haslong been known from the Antarctic seas , and another
(M. angustirostris) occurs in small and dwindlingnumbers off the coast of California . The sea elephantsare the largest of all the seals
,old bulls measuring
about 20 feet long ; but the females are very muchsmaller . The southern sea elephants (which , by theway , may or m ay not be all referable to a singlespecies) were in former times slaughtered in greatnumbers at Kerguelen
,the Crozets , and Heard Island
and in California the northern species was still p len tiful and vigorously pursued at the time of the rush tothe gold- diggings in 1 849 and following years .
The walruses form a family by themselves , theTrichechidae , containing one or perhaps two species ,for naturalists are not agreed as to whether the Atlanticand Pacific races of this animal should be looked uponas specifically distinct or not . However this m ay be , itis always , so far as I know,
easy to distinguish betweenone and the other
,for the tusks of Pacific specimens
are notably longer,thinner
,and more convergent than .
are those from the Atlantic region . Unlike the seals,which are fish- eaters
,the walrus lives upon clams
WALRUS AND EARED SEALS 407
that is to say , cockles , Myas , Mactras , and other burrowing shellfish , the digging out of which from the
sand and gravel seems to be the chief use of the greattusks . The walrus is now verging rapidly towardsextinction . In Spitzbergen , where thirty or fortyyears ago it was in prodigious numbers , i t is nowscarce
,and , in fact , the once great herds .which existed
in that region , at Nova Zembla, and in Greenland ,
are already a thing of the past'
. The Pacific walrus isconfined to a narrow stretch of coast in North-EasternAsia , and a still smaller part of the opposite Americancoast . Here in the early part of the nineteenth century Middendorff described them as existing in hundreds of thousands
,and even between 1 870 and 1 880
the tusks of about walruses were broughtannually to San Francisco by the American whalers .In the Pribylov Islands
,where they were still numerous
in 1 874 , I only saw in 1 897 a single dead carcass . Thewalrus has several times been known to wander to thenorthern and western coasts Of Scotland , the last timeabout 1 857 but we m ay take it as certain that such anevent will not happen again .
The Eared Seals , or Otariidae , form the third andlast family of the Pinnipedes . These include
,in the
first place , the genus Otaria , the Fur Seals , so wellknown for the international complications to whichthey have given rise . The genus does not occur inthe Northern Atlantic its distribution would seem tobe in the main Antarctic , from which ocean the rangeof one species to the Behring Sea appears to be a greatbut exceptional extension . Everywhere we have here arecord of exterminations
,and even in the Pribylov
Islands the herds are now but a shadow of their formergreatness . The chief breeding-places of Fur Seals are ,or were
,in the Antarctic region , at the Auckland
46 8 WHALES , SEALS , AND SEA- SERPENTSIslands , St. Paul , and Amsterdam Islands
,etc . (O .
forsteri) ; on Robben Island and some other SouthAfrican islands and coasts (O . antarctica) on variousparts of the South American coast
,where their haunts
often give rise to the name Lobitos Islands—11a ,the
islands of the sea-wolves—from Uruguay roun d CapeHorn to Chili and the Galapagos (O . australis) and
,
chief of all , in Behr ing Sea and the Pribylovs , theCommander Islands , and the Kuriles (O . ursina) . Theseveral breeding-grounds in the Kuriles have beenexterminated for about twenty years
,and it is said
that in the times of relaxed supervision during theJapanese War the Russian breeding-grounds of theCommander Islands were all but depleted . A Fur Sealrookery is one of the great sights of natural history.
The bulls come ashore in Spring each gathers togethera harem of as many females as he can attract to himself , and can defend by ceaseless combat from hisneighbours . The bulls remain at their posts all throughthe season
,never entering the water to feed ,
and bylate summer are gaunt and lean . At the height of theseason the long beach is a densely crowded mass ofbulls
,females
,and pups, in noise and stench and
ceaseless movement .
The genus Zalophus is allied , but differs in the wantof the fine fur of the Otarias . To this belongs theblack sea lion of the Californian coast . Thisanimal is very graceful and docile , and is often trainedfor menagerie purposes . Another species of the samegenus occurs on the northern coasts of Australia , and
northwards to Japan . One other genus is Eumetopias ,to which a single species , Steller
’
s Sea Lion , belongs .In contrast to the Fur Seals , which congregate ingreat rookeries in a few well-known spots , thesesea lions disperse in small colonies , and m ay be seen
41 6 WHALES , SEALS , AND SEA- SERPENTSvirulently poisonous , and fierce in their attack and myold master , SirWyville Thomson ,
used to tell comicaltales of the panic they sometimes caused among thenaturalists of the Challenger , when he and his col ~
leagues were wading among the coral reefs . They are
adapted in various ways for their aquatic life . Thehead is small and pointed the belly is not flattenedlike that of an ordinary snake , but sharp or keeledlike that of a herring the tail is flattened like
'
that of afish , but is at the same time prehensile , and the snakeclings by means of it , like a little sea-horse
,to weed or
coral . The lungs are of great size , and the nostrils havevalves which can be tightly closed , so that , on the onehand , the creature can dive with safety
,and on the
other hand it may float motionless on the surface ,buoyed up by its store of air . They are all viviparous .
They feed on fishes , and i t is said that the instant effectOf their poison is to relax the whole body of the fish,
so that it m ay be safely swallowed head foremost , itsspiny fins offering no obstacle in their relaxed condition . There are many kinds Of sea—snakes , belongingto several different genera . They are in most casesbrilliantly coloured ,
oftenin alternate rings of black andwhite
,sometimes adorned with green and yellow . In
Indian and other eastern harbours the passenger m ay
at times recognize their slender and gaudy shapes ,swimming in the clear water . The widely distributedHydrus platurus (or Pelamys bicolor) , a rather smallspecies
,conspicuous with its yellow belly,
‘
and themuch larger Distira cyanocin cta ,
more or less annulatedwith black ,
are perhaps the oftenest seen . Manyspecies are over a yard long , and the largest , D . grandis
(from Malay and North Australia) , is about 8 feet long .
Specimens 1 2 feet long are said to have occurred .
The sea- serpents of Aristotle and of Pliny seem to
SEA- SERPENTS 41 1
have been no more than immense eels , a family offi shes which contains many diverse , and in some casesgigantic
,kinds . A famous sea- serpent that came
ashore on Stron sa , in Orkney , in 1 808 , measured
56 feet long , and was carefully chronicled and described in the Transactions of the Wernerian Society
,
was almost certainly a huge oar—fish of the genusRegalecus . Sir Everard Home , it is true , identifiedthe two vertebrae which alone were preserved as thoseof the great B asking Shark ; but I have examinedvertebrae of both fish, and believe that , in a more orless mutilated condition , they might Well be mistakenfor one another
,even by an anatomist .
But the great sea- serpent is something other thanthese , and , whatever it may be , the many accountsof its appearance deserve a patient hearing and j udicialinvestigation . More things than one seem to have beenincluded under its name . I t is now that sea-beastLeviathan
,which God of all His works Created hugest
that swim the ocean stream in Milton ’s account ofwhich is mixed up the Eastern tale of Sindbad theSailor
,and the great whale on which he and his com
rades landed and built their fire . Again as the Krakenof Pontoppidan (who himself , however , distinguishesbetween the Kraken and the true sea- serpent) it ,
i sclearly recognizable as some sort of gigantic cuttlefish or octopus and of the same kind was also in allprobability the very long and frightful sea-monsterseen by the Rev . Hans Egede Off Greenland in 1 734 .
Now,though these latter denizens of the great deeps
come but seldom into the hands of competent observers ,yet we do know
,for certain
,that cuttle-fishes of enor
mous size exist in the various oceans . Professor Owendescribed one which came ashore on the Island ofAchill , whose arms were 30 feet long , and whose eyes
41 2 WHALES,SEALS
,AND SEA- SERPENTS
were great globes 1 5 inches in diameter ; and Pro
fessor Verrill has collected notes of a considerablenumber observed from time to time , chiefly on Newfoundland , whose arms ranged from 30 to 42 ~ feetin length
, and whose entire length ,body and arms
and all, were in some cases over 50 feet . We haveevery reason to suppose that these few stragglers thathave been stranded and measured give us but a veryimperfect idea of the dimensions that may actuallybe attained . Again
,in Japanese pictures and carvings
we have portrayed,with evident good faith and
accuracy,precisely Similar monsters of the cuttle-fish
kind . As has been already mentioned in these pages ,the Prince of Monaco has on several occasions discovered in the stomach of the SpermWhale the halfdigested remains of cuttle-fish,
great , if not SO great ,as these ; and it may be remembered that many storiesof the sea- serpent describe it as in combat with thewhale , and wrapping its long coils about the Cetacean
’
sbody . Dr . Andrew Wilson and (afterwards , and ingreater detail) Mr . Henry Lee have shown that manystories of the sea- serpent might be so interpreted as tocorrespond to j ust such gigantic cuttle-fish as Owen ,
Verrill , and the other naturalists have proved theexistence of . Thus in Hans Egede
’s drawing anddescription of his monster , with its spouting head and
writhing tail,both elevated high above the surface of
the sea,we seem to see the tail and one of the sinuous
tentacles of a great cuttle,whose head and
‘
rem aining
tentacles were still submerged .
Then , again,there are many other accounts , which
describe a more serpent- like animal , floating in hugecoils upon the sea,
such as that reported from theIndian Ocean by the Captain of H .M . S . Daedalus in1 848 , by the Officers of the barque Pauline in 1 877 ,
414 WHALES,SEALS , AND SEA- SERPENTS
of the Pinnipedia , in near alliance to the eared or furseals . We know that closely allied to these samePinnipeds was a certain gigantic creature of theTertiary Period—viz , Zeuglodon , or Basilosaurus asit was first called . This great mammal
,with small
head,serrate teeth , long neck , and huge , more or less
whalelike body , would , if we could believe it still tolinger on in existing oceans , be a sea- serpent indeed .
But whether the great sea- serpent be a giant cuttlefish or Zeuglodont mammal , ,
or whatever else it maybe
,to meet it on the high seas , with opportunity to
observe , sketch , and photograph it , is something forwhich the seafaring traveller may reasonably keep a
Sharp lookout,that he may see this marvel of all
marvels of the great waters,and m ay so help further
to °transmute this old tradition into the language ofprosaic science .
CHAPTER XI I I
LOGS, NOTES, AND LABELS ; ODDS AND ENDS
BY THE ED ITOR
LOGGING,note - taking , and labelling with cold ,
wetfingers form at best an unpleasant task even on a fineday ; they should therefore be simplified as far aspossible .
All note and log books should be bound in a glazedwaterproof cloth
,paged
,if possible
,with a white rag
paper rather than with a pulp paper ; on no accountwith paper of a highly sized surface . The notebooksShould be of a size to Slip easily into a pocket the sizeof logbooks will depend to some extent on the handwriting
,but 1 2 inches long by 8 inches high is a good
Size ; if they are to be used on deck , a thin sheet oflead (about 1 6 metal gauge) tacked on to one cover ,will prevent their being blown overboard . At night afair copy should be made of each day
’
s log , and theday ’s notebook glanced through ; this Often enableserrors and omissions to be detected while the facts arefresh in the memory .
All labels should be placed inside the bottle , exceptwith water samples . The paper should be selectedwith some care ; soft wood-pulp paper Should on noaccount be used . A vegetable parchment paper isgood
,but any good stout rag paper will serve the turn ,
if it does not rub away after soaking in water for somedays . Write with a B or BB pencil , or with Wolff
’
s
4 1 5
41 6 LOGS,NOTES , LABELS ; ODDS AND ENDS
808 5 0.“N Z N
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BR
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SEN
Re
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.
.
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41 8 LOGS , NOTES , LABELS ; ODDS AND ENDSChinese ink ; both of these stand years of immersion informalin or alcohol .Paper labels are unsatisfactory in the case of fish
preserved in tanks , for the friction caused by the motionof the Ship rapidly obliterates the writing . A foldedlabel , with the writing inside , will, however , be foundto stand fairly well if inserted in the mouth or underthe gill cover of the fish better still are the soft copperlabels supplied for use in gardening .
Three sample logs form pp . 41 6, 4 1 7 ,to be varied
according to the character of the work proposed ; theitalics represent examples , not real observations . If thetraveller does not intend to take detailed temperaturesand water Observations , everything at sea can be goton to the first pattern . The writer strongly recom
mends the principle of a number for each day midnight till and a letter for each operationthis method simplifies labelling , and enormously facilitates reference . Anyone who has worked over theReports of some recent expeditions , in which each kindof gear and observation had its special series of numbers ,will appreciate the advantages of a single series , and ofa Single printed table to which to refer .The log and note books cannot contain too many
details . Their value may not be apparent at once , butsomeone
,perhaps in twenty years ’ time , will find in
them just the clue that he is seeking .
It i s hardly possible to get out a log for the shorecollector ; he must rely chiefly on his notebook . Inthis case also it is a good plan to take a number for eachday ’s work
,subdividing it by letters according to his
fancy . The following points should always be noted .
Date ; locality (from W. side of Smith’
s Point for
two miles westerly) time noon to pm . ) tide
(half-ebb to L.W. , springs) weather (cloudy and blowy,
FATHOMS AND METRES 41 9
bar. 29 , falling) ; temperature ( of rock pools) ground(rocks with Fucus on the point, some pools, the rest
fine sandwith isolated rocks) . For animals and plantsnote the following kind of thing Dry or submergedin sand , or mud , or on rock under rocks or stonesadhering or washed out from weed or rock sifted outo f sand ; relation to H .W. and L .W. marks
,etc . A
specimen by itself has very little value ; a specimenwith full notes of its habits and habitat is a discovery .
CONVERSION OF FATHOMS AND METRES .1 fathom metres2 fathom s 3 6576
5 4864
7 3 1 52
9°
1440
109 728
14 63041 6 4592<
5
cowGun
-le
t»
A little u se of the decimal point will enable any conversionof fathom s into metres, or the converse . Thus , suppose thatit is desired to find how m any m etres are equal tofathom s
fathom s : m etres500 9 14
-
40
30
1 28 0
1,53 7 fathom s : m etres
THERMOMETR IC CONVERS ION .
The following tables can be used for air temperatures ando rdinary work but , as having only one place of decim als ,they are not accurate enough to satisfy the m odernhydrographer .
1 metre 05 468 fathom2 m etres : I
‘
O936 fathom s1 6 4042 1 872
27 341
3 28093 8277
kO
OO\1
GUI
-P
U)
CONVERSION OF CENTIGRAD E INTO FAHRENHEIT .
Exam p le—to convert 1 7 6° C . Gen eral fo rm u lainto Fahrenheit
I 7°O
OC . F .
C .+ 32
06°C . F .
oC
1 76°C . F .
CONVERSION OF FAHRENHE IT INTO CENTIGRADE .
422 WIND AND WEATHER SCALES
WIND , WEATHER ,AND FOG SCALE S .*
Description .
CalmLight breeze
Moderate breeze
Strong wind
blue Sky .
clouds , detached .
drizzling rain .
wet without rain .
fog .
gloomy .
hail .lightning .
m isty .
overcast .
Intensity can be indicated by underlining . Duration ofrain,
hail,snow
,and sleet should always be recorded,
and
can be indi cated by a numeral preceding the letter thus51 = five hours of rain .
Abbreviated from those issued by the Meteorological
W IND .
WEATHER .
Descrip tion .
StrongwindGale force9 ,
Storm forceHurricane
Office revised form of B eau fort’s scales .
passing showers .
squally .
rain .
snow .
thunder .
ugly appearance o fweather .
objects unusually visible .
dew.
haze .
FOG SCALE 423
FOG.
D escription .
No fog or m ist , horizon clear .Light fog or mist , horizon invisible ; objects visible
at working distances .
Moderate fog ; lights , passing vessels, and landmarksgenerally indistinct under a m ile . Fog signalssounded .
Thick fog ; ships’ lights and vessels invisible at
quarter-mile or less .
MARINE STATIONS
IT is hoped that this section may prove useful to travellersin need of local information . Even those State or Officialstations m arked t ,
which are not open to researchers fromoutside , m ay be relied upon in moSt cases for advice and
assistance .
This list has been revised by m eans "of Professor C. A .
Kofoid’
s Biological Stations of Europe (US . Bureau ofEducation) , Washington ,
1 910,which contains full descrip
tions and photographs of the stations , boats, etc . AssistantD irectors are marked A.D.
424 MARINE STATIONS
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4 30 ANIMAL CLASSIF ICATION
CLASSIFICATION TABLES
THE SE c lassification s are intended s im p ly as a ready m ean s
for the untrain ed observers to p igeon -ho le the form s m en tion edin the book . The ir aim is p ractical accord ingly they do n ot
.c on tain all the latest recondite p olysyllables wh ich are to be
found in the sp ec ial istic m em o irs .
ANIMALS .
Protozoa (On e-Celled An imals) .I . Gymnomyxa
I . Foramin ifera( I ) Imp erforata.
(2 ) Perforata.
2 . Radiolaria( 1 ) Perip ylaria.
(2 ) Monopylaria.
( 3 ) Tripylaria.
(4 ) A can tharia.
Corticata1 . Ciliata.
2 . Euflagellata.
3 . Cystofiagellata.
4 . Din ofiagellata.
Astrorhiza, B iloculina, Cornusp ira, Lit
uola, Miliola.Globigerin a, Nodosaria, Nummu lina.
Orbulina, Pulvinulina, Rotalia, Text
ularia.
Collozoum , Heliosphwra, Thalassicolla,
Eucy rtidium , Stylosp ira.
Challengeron , Coelodendrum , Con chidium , Euphysetta, Tuscarora.
A can thom etra.
Noctiluca.
Ceratium , Peridin ium .
Metazoa (Man y-Celled An imals) .1.Porifera, or Parazoa (Sponges ) :
1 . Calcarea.
2 . Myxosp ongiae.
3 . Hexactin ellida.
4 . D em ospongiae.
Coelen terataI . Hydrom edusae (jelly
fish and their fixedhydro ids ) .
2 . Siphonophora (jellyfish)
( 1 ) Calycon ectw.
( 2 ) Physon ectae.
( 3 ) Cyston ecta .
(4 ) Disconectae.
Eup lectella (Venus’s flower-basket) .Hyalon ema.
B ougainvillea, Cladocarpus , Euphysa,
Millepora, Obelia, Phialidium .
D iphyes .Physophora.Physalia.Porp ita, Velella.
ANIMAL CLASSIFICATION 43 1
3 . Scyphom edusae (jelly Aurelia, Pelagia, Rhiz ostom a.
fish) .
4 . Anthozoa( r ) A ctin iaria (an Arachnac tis, Min yas .
em on es ) .
(2 ) Alcyon aria (false Alcyon ium , Corallium , Gorgon ia, Helicorals ) . Op ora, Penn atula.
3 ) Madreporaria Cary0phyllia, Lep tOp enus, Madrep ora.
tru e corals) .5 . Ctenophora (jelly-fish) . B eroe , B olin a, Cestus , Pleurobrachia.
I I I . Turbellaria, or Planaria (flatworm s) .
Nemertin a, or Nem ertea.
V. Trematoda (flukes) .
VI . Cestoda (tap eworm s) .
VI I . Nematoda (roun dworms) .
VI I I . Sipun culoidea.
IX. Chaetop oda (bristle-worm s)1 . Archiann elida. Polygordius .
2 . Polychaeta( r ) Phan erocephala. Amphin om e , Autolytus , Aphrodite ,
Chaetop terus , Herm ion e , Hyalin .
o ecia, Nerin e , Palolo , Tomopteris,
(2 ) Cryptocephala. Sabella, Serpula.
2 . Oligochaeta (earthworm s) .
3 . Hirudineaaeeches) .
4 . Echiuroidea (spoonworm s) .
5 . Rotifera.
X. Crustacea :
r . Cladocera (B ran chio Evadne .
poda.
2 . Ostracoda. Con choecia.
3 . Cop epoda. Calamus , Caligu s, Sapphirina, Tem ora.
4 . Cirrhipedia (barnacles) .
5 . Cum acea. Cum a .
6 . Amphipoda . Caprella, Ep im eria, Euthemisto, Phron im a .
Isop oda. Girolama, Rocin ela, S erolis .
Stom atopoda . Squilla .
Schizopoda. Euphausia, Mysis , Nyctiphan es .
Decapoda.
( I ) Macrura (lob
ster group ) .
(2 ) Anomura (her
m it group ) .
( 3 ) Brachyura(crab group ) .
Acanthephyra, Eryon , Lucifer, Ne
phrops , Palinurus , Penaeus, Ser
gestes , Willem oesia.
Callian assa, Catapagurus, Galathea,
Mun ida, Pagurus .
A telecy'
clus, B athyn ectes , Corystes .
Cryp tochirus , Ebalia, Hapalocar
cinus , Hom olodromia, Maja, Por
tunus, Thia.
432 ANIMAL CLASSIF ICATIONXI. Insecta . Halobates.
XII . A rachn ida (sp iders , Desis .
XI I I . Pycnogon ida. Pycnogonum.
XIV. Mollusca (shellfish)r . Gastropoda. Atlanta, Archidoris , Carinaria, Chiton ,
Clione , Doris , Eolis , Glaucus , Hyalea ,Jan thin a, Styliola.
2 . Lam ellibranchiata. Lithodomus .
3 . Cephalop oda. Argonauta, B enthoteuthis , E ledone ,
Loligo , Nautilus , Octopus, Sep ia,
Sep iola, Sp irula.
XV. Polyzoa or B ryozoa. B owerbankia, Cellularia.
B rachiop oda (lamp -shells) . Terebratula.
XVI I . Echin odermata
1 . Holothuroidea (tre Cladodactyla.
pangs ) .2 . Crin oidea (feather An tedon , Rhizocrinus.
stars ) .
3 . Echinoidea (sea Echinus , Salen ia.
urchins) .4 . Ophiuroidea (brittle Ophioglypha.
stars) .
5 . Asteroidea (starfish) . Archaster.
XVI I I . Chaetogn atha. Sagitta, Spadella.
XIX. Chordata
1 . Urochordata, or Tu App endicularia, Doliolum , Pyrosoma,
n icata. Salpa .
2 . Hem ichordata. B alanoglossus (En teropneusta) .3 . Cephalochordata Amphioxus .
(lan celets ) .4 . Cyclostom ata (lam
p reys ) .5 . Pisces (true fish) .
( I ) Chondrop terygii Raja,Chimaara, Scyllium .
(sharks and
rays ) .(2 ) Teleostomi Argyrop elecus , Gadus, Gobius, Lepado
(bony fish) . gaster, Macrura, R egalecus. Scop elus,Scorpaena, Solea, Stomias .
6. Ophidia (snakes) . Hydrus. Distira.
Cetacea (whales)( r ) Mystacocoeti. B alaena, B alaenop tera, Megap tera.
(2 ) Odon tocoeti. D elphinus , Monodon , Orca, Phocaena ,
Physeter.
Pinn ip edia (seals) . Otaria, Phoca, Trichecus .
LITERATURE
ONLY the merest outline of a guide to the literatureof the subj ect can be given here . A general view o fterrestrial phenomena , popularly written butscientifically sound ,
is furnished by Dr . H . R . Mill ’sRealm o f Nature Further Wyville Thomson ’sDepths of the Sea ,
Alcock ’s Naturalist in IndianSeas , Moseley ’s Notes by a Naturalist on H .M.S .
Challenger , and Three Cruises of the Blake,by
Agassiz , supply accounts of typical expeditions whichare excellent and valuable reading . In Kriimm el
’
s
Handbuch der Ozeanographie we have a textbookof pure oceanography (excluding zoology and botany) ,written with a thoroughness and wealth of detail trulyTeutonic , but suitable only for somewhat advancedstudents .
From these we have to plunge almost at once intothe more technical monographs . As a rule the mostvaluable are those of the more recent expeditions—theNational or Plankton Expedition (North AtlanticOcean) the Valdivia (Atlantic and Indian Oceans) ,the Siboga (East Indies) and the Belgica (An tarctic) —but many of the Challenger Reports are
still indispensable . The maj ority of these are zoologicalan d botanical reports , but there are also volumes dealingwith Chemistry ,
physics , meteorology , and equipment .The monographs o f the Naples Station are the bestguide in some groups . Once the observer has selected
43 4
LITERATURE 43 5
his subj ect or his group , he will make a selection fromthese sources .
Beyond them lies the nebulous myriad of papersscattered in technical j ournals . For zoologists thebest path is the card- catalogue prepared by theChallenger Society by this means it is possible to
find all that has been published on the marine faunao f a region , or even of a lonely island . But manyReports of Expeditions contain very full lists of special
p apers .
General zoological and botanical textbooks of all
grades are only too numerous . For the purposes ofthe reader whom we have in mind
,the volumes of the
Cambridge Natural History are to be recom
mended,and on the botanical side Murray ’s Intro »
duction to the Study of Seaweeds will be foundhelpful . Anatomical and systematic textbooks areb eyond the scope of this work .
I . THE A IR .
In stru ction s for Keep ing the Meteorologic al Log,‘
B arom etr ic Manual for the Use of Seam en,
and
other publication s of the Meteoro logical Office .
Atm ospher ic C ircu lation Chal lenger R eport by D r .
A . B u chan .
B artho lom ew ’
s Phys ical Atlas,
vol. i i i .Ozean ograph ie and Mar itim e Meteoro logie Vald iviaR ep ort by D r . A . Schott .
Hin ts to Meteoro logic al Observers W . Marr iott .
Seas an d Skies in Many Latitudes Hon . R . Abercrom bie .
For Sp ec ial seas ,the P ilot
,W ind
,and Curren t Charts of the
Meteoro logical Office ; also the Adm iralty PilotsSailingD irection s , ” and Charts .
I I . THE WATE R .
I . Ocean ic Circu lation Challenger R ep ort by Dr . A .
B u chan .
Num erou s Publication s de C ircon stan ce issu ed by theCon se il Perm an en t In ternational p our l
’
Exp loration
de la Mer .
436 LITERATURE3 . The Norwegian Sea B . He lland Hen sen and F . Nan sen .
4 . Hydrograph ical Tables M . Knudsen .
5 . The Tides and Kindred Phen om ena of the Un ited Kingdom Sir G . H . Darwin .
See also I Nos . 3 , 4 , 7 .
I I I . THE SHORE .
Coral R ee fs Charles Darwin .
Corals and Cora l Islands J . D . Dana .
An im al Life Car l Sem p er .
Physical Geography F . M . Davis .
Les D epots Marin s L . W . Collet .
Maldive and Laccad ive Arch ip elagoes CambridgeUn iv . Press .
See also I . , No . 7 .
GUI
-D
UJ
SO
H
IV . THE PLANTS .
Pflan zenleben der Hochsee G . Schu tt.
Meeresalgen D eu tschlands u nd Oesterreichs F . Hauck .Phy cologia B r itann ica W . H . Harvey .
Nere is B oreal is-am er icana W . H . Harvey .
Nere is Au stralis W . H . Harvey .
Phy cologia Australica W . H . Harvey .
Mar in e A lgae ofNew England W . G . Farlow .
Som e Aqu eou s Media for PreservingAlga Setchel l andOsterhout, B ot . Gaz .
,xxi .
,1 40.
V . THE FLOAT ING AN IMALS .Planktonkunde A . Steuer (an adm irable book
, and
the only on e wh ich deals with the who le subj ect) .Nord isches Plankton b y variou s authors
,for work in
the North A tlan tic and dep enden t waters .
For sp ec ial group s the R ep orts of the Exp edition s c itedabove shou ld be u sed ,
and con tain referen ces to theprevious l iterature .
VI . THE SEA FLOOR .
I . Deep Sea Deposits Challenger R eport, by Murray andR enard .
3
2 . Grund Proben Valdivia R eport , byMurray and Philipp i .3 . R ep ort of the A lbatross Exp edition ,
1 9 04- 1 905 A .
Agassiz , in Mem . Mu s . Com p . Zoo l . , xxxiii .
VII . AN IMALS OF THE SEA FLOOR .
Grundziige der Mar inen Tiergeographie A . Ortmann .
See also rem arks under V .,No . 3 .
43 9LIST OF FIRMS RECOMMENDED
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442 INDEX
A scophyl lum ,1 43
A sp erococ cu s , 1 3 9A sp iration p sychrom eter
,1 6
A stero idea . See StarfishAstrorhiza
,80
Atelecy c lu s , 2 60
A tlan ta , 1 8 2 , 185A tm osphere ,
c ircu lation, 4
- 1 1
daily variation,22
descrip tion ,1
, 2
p ressure ,1—1 1
tem p eratu re ,1 1
,1 2
er , 2 2
Atoll , 88, 98 , 99A ur icu laria o f trep angs , 186Au tolytu s
,1 7 5
Azores,84
B ac teriastrum, 118
B aillie sou n der, 201 , 202
B ait , 74 , 7 5 , 3 2 9B alaen idae , 3 86
-
3 9 1
B almn op teridae , 3 9 1-
3 9 6
B alan oglossu s , 76 , 1 00,1 88
B alloon s fo r u p p er cu rren ts , 2 1
B arn ac les . See Cirrhip edia
B arograph ,1 4
B arom eter, an eroid , 1 4
m ercu rial , 1 3 , 1 4B arr ier ree f
,8 7 ,
89B athybiu s ,
205B athyn e cte s , 2 45B eam trawl . S e e TrawlB eau fort ’
s s cale s , 42 2 , 42 3B e luga , 3 9 9B en thoteu this , 258B erardiu s , 3 9 9B erm u da ,
8 5 (bis )B eroe ,
1 7 2 : 3 74B ilo cu lin a c lay ,
2 1 4B io logic al station s , 42 3
—42 9
B ip in n ar ia of star -fish, 186
B ip olarity , 2 5 7B lac k Sea , 2 2 6
B lu e algae . S ee Cyan ophyceaeB o lin a
, 3 49 , 3 7 5B ore0phau sia , 3 9 5B orn etella , 13 5 , 140B ottle - n ose whale , 3 9 8 , 3 89B ottles ,
storage ,for an im als
3 6 1-
3 64for water sam p les , 3 3 ,
3 4
B ottom dep osits . See D ep ositsB ougainvillea , 170, 171B ou lder zon e
,8 7
B rachiop oda (lam p shells) ,2 49
B rachyura,bottom , 245
of p lan kton ,1 80
p reservation , 3 80
B ran chiop oda ,2 44
B rittle - stars larva ,1 84 , 186
of bottom , 2 3 7 , 246B rook , L ieu ten an t , U .S . Navy
,
200
B rown alga See Phaeophyc eaeB u cket for water sam p les , 3 4
Ca’
aingwhale , 3 84 , 3 9 9Cables as c olle ctors
,265
Cachalot . See Sp erm whaleCalamu s , 177 , 3 9 4Caligu s , 177Callian assa larva , 181Calothr ix ,
1 3 4 , 13 6Caly con ectae, p reservation , 3 72
Can aries ,84
Cap e Verde Islan ds ,84
Cap rella , 2 44 , 265Cap stan , steam , 267Car in aria , 1 82 , 185Caryophyllia , 3 7 5Catap agu ru s , 254Cau lerp a , 1 3 5 , 1 3 8 , 140Cellu laria , 259Cen tigrade i n t 0 Fahrenheit420
Cep halo chordata . See Am phioxu s
Cephalop oda . See Cuttle-fish
Ceratium ,1 20,
1 2 1 , 122,1 64
Cetacea . See WhalesCestoda , p reservation , 3 78 , 3 79Ce stu s ,
1 7 5 , 199Chae to c eras ,
1 1 7 , 119
Chaetogn atha ,1 7 5 ,
Chaetom orpha ,1 2 6 ,
1 3 5 , 136
Chaetop oda (br istle -worm s ) , 1 75 ,
larvae , 176
p reservation , 3 76 , 3 7 7Chae top teru s , 176, 2 4 1
Challenger ,v
dredge rop e ,2 7 2 11 .
sam p le dep o sit ,2 1 5
INDEX 443
Challenger ,H UM S sou n d1ngs ,201
Challenger Soc iety ’s region s ,
2 5 5 , Chart V I I I .Challengeron , 167Chem icals for p reservation , 3 473 6 1
Chim aera egg c ap su le , 3 17Chiton , 2 47 , 25 8Chloreton e , 3 6 1
Chlorophy cea (green algae) , 1 1 6Chon dr ites , 2 1 0
Christm as Islan d ,85
Chrom atophores ,1 1 7
Chrom ic ac id, 3 5 9
Chrom o -ac etic ac id , 3 5 9Ciliata
,1 64
Cirolan a , 177Cirrhip edia ,
1 78 , 244Naup liu s , 181
p reservation , 3 79Cladocarp u s , 23 8Cladoc era ,
1 7 8
Cladophora , 1 26 ,1 3 5 , 136
Claudea,1 26 , 1 5 2 , 155
Clay , red . Se e R ed c layClion e , 185C losed seas
,63 , 2 2 6 , 2 2 7
C lou d observation s,1 9
Cocain e, 3 60
Co c colithophoridaa, 1 24Cocc osphaera ,
1 1 4 , 1 24 , 125 ,
2 20
Coeloden drum, 167
Coelen terata o f bottom , 2 3 52 3 9 .
See a lso Hydro ids , Je l lyfish
Collo zoum, 1 64
Con chidium , 1 67Con choec ia
, 177 ,1 78
Con stan tin ea , 1 5 2
Con tin en ta l she lf,207 , 2 2 7 ,
2 3 1
2 3 3an im als of
,2 3 4
- 2 6 1
slop e , 208 ,2 2 7 , 2 3 1 ,
2 3 3Con tin en ts ,
form er c on n ection s8 3in stability
,2 2 8 - 2 30
Cop ep oda , 1 7 8 , 2 44
p reservatio ri , 3 7 9 Darkn ess . See L ight
Cop ro litic m u d,2 1 4 D arwin ,
theory o f c oral ree fsCoral an em on es ,
89-
9 4 , 3 7 5 9 6
Coral , dep th , 9 4m u d
,1 00
, 2 26
oolite an d bre c c ia , 86rate of growth , 9 2
reefs an d islan ds , 8 2 - 1 05c om p osition , 9 4d isin tegration , 1 00, 102
theories , 9 6 et seq .
Coral lin a , 1 2 7 , 1 5 1
Corallin acea , 1 50- 1 5 2
Coral lin e Zon e, 2 3 1
Coral lium , 2 3 7Corona , 2 3Coron u la , 3 9 5Corrosive sublim ate ,
1 1 1, 3 5 6
Cory stes , 2 60
Cosc in odiscu s ,2 20
Co sm ic du st , 2 1 0, 218 , 2 30
Cretac eou s p eriod , land of, 83
Crin oidea . See Sea - liliesCru stacea , c o lle ction , 7 4
m ou lts , 1 80- 1 82
of bottom , 24 1- 246
of deep sea , 2 63 , 2 64of p lan kton , 1 7 8
- 1 8 2
p reservation . 3 79 , 3 80
Cryp to chiru s , 7 8
Cten ophora ,1 7 5 , 3 49 , 3 74
Cum acea ,2 44
Curren ts ,e ffe ct on an im als , 2 5 2
on p lan ts , 1 3 1
gen era l ac coun t , 5 7- 64
m eters , 5 3-
5 7 ,63
- 64m idwater , 63
Cutleria ,1 3 9
Cu ttle -fish ,1 83 ,
2 48 ,2 49
as sea - serp ents , 4 1 1-
4 1 3 ,
in rocks , 7 8
Cyan ophy c ea (blu e alga ,or
Myx0phy cea ) , 1 1 6,1 24 ,
1 2 7 ,
I 3 4Cy clom c storm s , 9
- 1 1
Cym odocea , 7 3Cym op olia , 140Cy ston ecta , p re servation , 3 7 3Cystophora , 404Cy stophy llum ,
1 43Cy stoseira ,
1 43
444 INDEX
D ecap oda p reservation , 3 80
D eep s ,206
Deep- sea an im als , 2 6 1 - 265c on dition s , 2 2 8 , 2 29dredging an d trawling, 2 7 1
2 7 7fish , 3 2 1 , 3 24soun ding,
2 7 7- 2 79
D elesseria ,1 26 , 1 5 2
D elphin ap teru s , 3 89 , 3 9 9D e lphin ida , 3 9 9
-
402
D elphin u s , 401
Dem ersal fish eggs , 3 1 6 , 3 17 , 3 1 8
322D ep o sition ,
rate o f, 209 , 2 2 9D ep osits , an im a ls in
, 2 86 , 2 8 7chart sym bols , 42 1
c lassifi cation , 2 1 3c ol lection , 203
- 205descrip tion , 208 -2 26
errors of exam ination , 2 1 4form for descr ip tion ,2 1 5
on c on tin en tal border , 2 2 72 2 8
radium in , 2 30
sam p le s of, 2 8 7thickn ess ,
209D ep th ,
an im al p lan kton ,1 9 2
oc ean , 205- 208
p lan ts ,1 2 9
D esis, 7 9
D esm arestia ,1 26
D eviation of win ds, 5
D iatom s , 1 1 6- 1 1 9in dep osits , 2 1 2ooze , 2 1 3 , 2 1 4 , 2 1 7 , 2 1 9
D ictyon euron ,1 42
D ictyota ,1 43 , 145
D ictyotac ea ,1 3 8 ,
1 42 ,1 43
D o ldrum s ,6
D in es ’
an em om eter ,1 7
D iphyes , 172D iscon ecta , p reservation , 3 73D istira , 4 10
D istr ibu tion of bottom an im als2 5 2
- 264of floating an im als ,
1 9 1
1 9 6
of p lan ts ,1 3 2 ,
1 3 3D iurnal variation , 2 2 , 3 2
D ol iolum ,l ife -history , 1 86 , 187
1 88
Doliolum , Phrom ina in ,1 80
p reservation , 3 8 1
D oridida , 2 48
Dredges , 2 89- 2 9 2 , 296
for p lan ts ,1 5 3
shooting an d towing,29 2
2 9 5Dredging, Chap ter IX . , 2 89
2 9 5deep
- sea , 2 7 1- 2 7 7
shallow , 2 80- 2 8 1
sorting catch ,2 85 , 2 86
D rift currents , 5 7n et , 3 3 6 , 3 3 7 , 3 3 9
D u rvillea,1 43 , 149
Eared seals , 407-
409E balia , 2 45E chin oderm ata ,
bottom , 2 3 7 ,
2 40
deep-sea , 263larva , 186
p lan kton ,1 84
E chin o idea . See Sea -urchin sE chiu ro idea , 2 40
E cklon ia ,1 26
,1 3 2 , 140, 1 42
E cto carp us ,1 3 8
Egregia ,1 42 , 144
E isen ia , 1 42
E km an’
s c orre ction table for
therm om eters , 43curren t m eter , 5 3
-
5 6 , 5 5 ,1 02
E ledon e , 259E levation of land ,
67-69
E n terom orpha , 1 3 1 ,1 3 5
Enterop n eu sta . See B alan oglossu s
E n tom ostraca , 2 44Eolidida , 248
E olis , 258Ephyra ,
1 69 , 171Ep im eria , 254E rign athu s , 404E ryon ida ,
2 64Eu cheum a
,1 6 1
E u cyr tidium , 166Eum etop ias , 408
Euphau siac ea , 2 45 , 3 9 5Eup hy sa , 170E u phy setta , 167E u them isto , 177Evadn e , 177 , 1 7 8
446’
INDEX
Histriophoca , 405Ho lothuro idea . See TrepangsHolten ia
, 236Hom o lodrom iida , 264Hom otherm ic layer of air
,20
Ho rm ogon ia ,1 3 4
Horm osira ,1 43 , 149
Horse latitudes , 7Hum pback whale , 3 84 , 3 9 4
-
3 9 6
Hurr ican e ,1 0
Hyalea , 185Hyalin oec ia , 2 4 1 , 250Hydro ids
,1 68—1 7 1 , 2 3 5
p reservation , 3 69Hydrom edu sa ,
1 68 , 1 69
p reservation , 369—3 7 1
Hydrom eter , 5 2 , 5 3Hydrophida , 409 , 4 1 0
Hydru s , 7 9 , 4 1 0
Hyp eroodon , 3 9 8 , 3 89
Ian thin a ,1 82
Ice -born e m aterial 209 , 2 1 1 , 2 1 2
In ia , 402
In sects ,1 84
In su latingwater -bottle , 3 7-
42
Irida a ,1 47
I slan ds ,c lassification ,
82
I sobar ,a l in e drawn through
p oin ts of sim ilar atm o spher icpressure
I sobaric charts , 5
gradien ts ,6
,1 0
,1 1
I sohalin e , a l in e drawn through
p o in ts of sim ilar saltn essIsohalin es , 30
I sop oda o f bottom , 244of p lan kton ,
1 80
p reservation , 3 7 9I sotherm ,
a lin e drawn through
p oin ts o f sim ilar tem p eratureI sotherm al layer o f air
,20
Jars for storage , 3 64 , 3 65
Jelly-fish ,1 68 - 1 74
p reservation , 3 69-
3 75
Kelp . See Lam inar iaKelvin ’
s sou nder , 2 8
Killer whale , 3 9 9Killing an im als ,m ethods , 3 45Kite s ,
m eteorological , 20, 2 1
K o foid’
s water -bottle ,1 1 6
Kogia , 3 9 8Krakatoa , du st from , 2 1
K r iimm el on Sargassum ,1 46
1 47
Labels , 3 66 , 3 67 , 4 1 5 , 4 1 8
Laboratory , yacht ’
s, 283
-288
Lagena ,8 1
Lagen orhyn chu s , 401
Lagoon ,87 et seq . ,
1 00 et seq .
Lam ellibran chia , bottom ,2 48
p lan kton ,1 82
p reservation , 3 8 1
Lam inaria,1 3 1 ,
1 3 9 ,1 42 ,
1 5 8
1 6 1
Lam inar ian zon e,2 3 1 ,
2 3 2
Lan d breeze,8
stu dy of, 66- 69Lauren c ia ,
1 5 2
Le B lan e sounder , 2 77 ,2 79
Lepadogaster , 3 1 8
Lep tonyx , 406
Lep top enu s , 237Lesson ia ,
1 42 , 144L ight , e ffect on p lan ts , 1 28 ,
1 29 ,
2 3 4
p en etration of,L in es . See FishingL in e squall , 9L ithodom u s
, 7 8
Lithophyllum ,1 5 1 , 160
L ithotham n ium, 7 3 , 9 4 , 9 5 ,
1 2 7 ,
Littoral dep osits ,2 1 3
region ,1 2 8
,1 2 9zon e ,
2 3 1 , 2 3 2 . See alsoShore
Lobodon , 406
Lobosp ira ,1 43
Lobsters , 2 45Logs , 4 1 5
-
4 1 9Lohm an n
’
s p um p ing m ethod ,
1 1 5Lol igo ,
2 48
Long l in es , 3 30- 33 3
Lu cas sou nding m achin e ,203 ,
Lu c ifer , 183Lum in o sity o f an im als , 262 ,
264Lyngbya ,
1 3 4
Macrocystis , 140, 1 42Macrorhinu s , 406
INDEX 447
Macrura (Cru stacea) My stac c eti (Whalebon e whales) ,of bottom , 2 45 3 86
-
3 9 6
of p lan kton ,1 80 Myx0phy c ea . See Cyan ophy
Macrurida (fish ) , 3 2 1 c ea
Madrep ora , 90Madrep oraria , 2 3 7 . See CoralMangan ese n odu les , 2 1 1
, 2 1 4
218Marin e station s , 42 3
-
429
Marten sia ,1 5 2
Mauritiu s ,84
Maury , Adm iral , 3Mean sphe re leve l , 2 2 7 11 .
Med ic in e ,1 07
Mediterran ean , a c losed sea , 63Medusa ,
1 68 - 1 7 2
Megalop a larva , 181 , 1 82
Megap tera , 3 84 , 3 9 4-
3 9 6
Melob esia ,1 5 1
Men thol , 3 6 1Mercury bichloride , 3 5 6 3 5 8
Meridian s ,fore ign , 42 1
Mesop lodon , 3 9 9Metazoa ,
1 63Meteorological Office ,
B ritish, 3Germ an an d Am erican , 4in strum en ts ,
1 2 - 1 7 ,1 9 ,
2 1
Meteoro logy , Chap ter I . See
also Atm osphere ,W ind , etc .
Methylated sp ir it . See A lcoho lMetre s in to fathom s , 4 1 9
Metric conversion s , 4 1 9 ,240
Microsc op e ,2 85
Midwater c u rren ts , 63stu dy , 1 9 2
trawl , 3 4 1 , 3 42Miles , n autic an d geographic42 1
Miliolin a , 80Millepora , 91 , 100, 93Mitraria , 176Mollu sc a ,
bottom ,247
- 249
p lan kton ,1 82
,1 83
p reservation , 3 8 1
shore c o llection , 74 et seqMon achu s , 405Mon odon , 3 89 , 400Monostrom a , 1 26 ,
1 3 5Mon soon ,
8
Mon thly Pilot Charts , 4Mud lin e
, 2 2 7Muds , 2 1 3 ,
2 24- 226
Mysidac ea , 2 45
Nan sen -Pettersson water -bottle3 8
Nan sen’
s soun der,204
Narwhal . See Mon odon
Naup l iu s ,1 80
, 181 , 1 8 2Nau tica l m ile , 4 2 1
Nautilu s,1 83
p ap er . See Argonauta
p ear ly , 1 83 , 2 48
N em al ion , 1 5 0
N em atoda , p reservation , 3 7 8
3 79Nem ertina
,2 40
N eobala n a, 3 9 1
Neom eris ,1 3 5
N ephrop s , 2 60
N ereida,1 7 5
N ereo cystis , 1 42 , 145N erin e , 176N er itic p lan kton 1 9 1
N ero D eep , 206
N ets . See Tow n et TrawlD redgefishing,
dip , 3 3 4 , 3 3 5drift , 3 3 6 , 3 3 7 , 3 39
gi ll , 3 3 5han d
, 3 3 3 , 3 3 4se in e , 3 3 9 -
3 4 1
tram m e l, 3 3 6
-
3 3 8
young fi sh, 3 4 1 , 342,
3 43N ipp er ,
2 7 5 , 276N octilu c a ,
1 64 , 167Nodosar ia ,
80
Nothe ia ,1 43
N o to chord ,1 84
Nud ibran chia , bottom ,248
p re servatio n , 3 8 1
N y ctiphan es , 179 , 2 2 7
Obelia , 171O cean ic Ci rc u lation , 5 7
-64fishes , 3 20-
3 24
p lan kton ,1 9 1
Oc ean s , dep th of,205
-208
p erm an en c e of,2 2 9
Octop u s . See Cuttle -fi sh
Odom eter ,2 76 ,
2 8 1
448 INDEX
Odon toc eti , 3 9 6-
40
Oiling sheave s , 2 7 7wire rop es ,2 74 , 2 79
Omm atophora , 406
Ophiu ra ,2 46
Ophiuro idea . See B rittle - stars
Orbu lina ooze , 2 1 4Orca , 3 9 9Orn itho c ercu s
, 122Ortm an n
’
s c oastal region s , 2 5 3Osm eru s
, 3 9 5Osm ic ac id
, 3 60
Ostracoda o f bottom, 244
o f p lan kton , 1 78
p re servation , 3 79Otar1ida
, 407-
409O tter trawl . See Trawl
m idwater , 3 4 1 , 342Oudem an s on the sea- serp en t
4 1 3Ou tfit , trop ical , 1 05
- 1 1 2 ,1 5 6
Oyster larva , 185
Padina ,1 43
Pagurida , 245Palin uru s larva ,1 82
Pa lo lo , 2 4 1Pelagia , 172Pelagic (high—sea or ocean ic )dep osits , 2 1 3 ,
2 1 6- 2 2 3fish eggs , 3 1 6
-
3 1 8 , 322Pelam y s , 4 1 0Pelvetia ,
1 43Pena u s larva , 181Pen eida , 2 64Pen erop lis ,
80
Pen ic illu s ,1 3 5Pen n atu la , 23 9Perforating alga ,
1 3 5Peridin iales ,1 1 6
,1 20
,1 2 1
Per idin ium , 123 , 1 64Petersen ’
s you ng-fish n et , 3 4 1
3 43Pha ophy cea ,
1 2 7 ,1 3 8
Pha osp ora ,1 3 8
Phialidium , 170Phoc ida , 403
-
406Phosphorescen ce . See Lum in
os1tyPhotographic app aratus 108
Phron im a , 177 , 1 7 8
Phy llophora ,1 3 3Phyllosom a ,1 82
, 183
Physalia , 172, 1 74 , 3 7 3Physeter . S ee Sp erm whalePhy son e cta , p reservation ,
’
3 72Phytop lan kton . See Plants ,floatingPian o -wire, 2 7 7Pic r ic ac id , 1 1 1 , 3 5 8 , 3 5 9
Picroform ol , 3 5 9Pillsbu ry m eter , 64Pilot charts,m eteoro logical , 4Pin n ip edia , 402
-
409Pin n u laria ,1 1 9Plan aria ,
2 40Plan kton , an im al . See An im alsfloatingp lan t . See Plan ts
,floating
as food ,1 63
Plan kton iella, 118Plan ts , Chap ter IV . , 1 1 3
- 1 6 1
c lassification , 43 3fixed,1 2 6- 1 6 1
c o llection ,
distribu tion ,1 3 2
ec on om ic u tility , 1 6 1
environm ent , 1 28 - 1 3 2
orders of, 1 2 7
p reservation , 1 5 7- 1 6 1
shore region s , 1 2 8floating, 1 1 3- 1 2 5
c ollection,1 1 4
- 1 1 6
p reservation ,1 1 6Platan ista , 402Pleurobrachia , 173 , 1 75 , 3 49 , 3 74Plu teu s larva , 186
Pollicip es , 7 8
Poly cha ta . See Cha top odaPolygordiu s , 176Po lysiphon ia ,1 2 6
,1 50,
1 5 2 , 154Polystom ella,8 1
Polyzoa , 9 4bottom ,249
p lan kton , 1 84 , 185
p reservation , 3 80.
Pon t0p0reia , 402Porcu p in e ,dredge 289 ,
296Por ifera . See Sp ongesPorphyra ,1 2 6
Porp ita , 173 , 3 73Porp o ises , 400Portunu s , 2 45Postelsia , 1 42
450 INDEX
SeaUrchin s ,bottom , 2 3 7 ,2 40, 242
preservation , 3 76
Sea water . See Waterweeds . See Plan tsSean . See Sein eSea - serp en ts ,
”
409-
4 1 4Seine n et , 3 39 -
3 4 1
Sep ia , 248 waterSep io la , 248
Sergestida , 1 80, 183Serolis , 2 5 2
Serp u la , 25 1Setchel l on p reserving p lan tsSeychel les , 83Shark eggs , 3 1 6
teeth in dep osits , 2 1 4 ,2 1 8
Shore , Chapter I I I . , 65- 1 1 2
collecting, 65- 82 , 3 10-
3 1 2
gear , 1 09- 1 1 2fishes , 3 1 0
-
3 1 3Shr im p s , 245Shrim p trawl . See TrawlSiboga , ac cum ulator , 2 75
sounder , 2 79S ieves , 204 , 205 , 286, 2 87S igsbee sou nder , 2 77 , 2 79S iphon ea ,
1 3 5S iphonophora ,
1 74
preservation , 3 72 , 3 73S ipun cu lo idea , 240
Snapp ers for deposits , 204 , 282Sole larva , 323Sotalia , 401 , 402
Sounding, 201- 203 , 2 7 7
- 2 79 , 28 1 ,
282
m achines , 2 77 , 28 1 , 282Spadellaf176Sp ec ific gravity , 30, 5 2
Sp erm aceti , 3 9 7Sp erm whale , 3 85 , 3 9 6
-
3 9 8
Spha rococ cu s ,1 6 1
Sp irit . See A lcoho lSp iru la , 1 83Sp lachn idium ,
1 26
Sp onges ,2 3 5
p reservation , 3 68 , 3 69Squalls , 9Squam ariac ea , 7 3Squ id . See Cuttle -fish
Squ illa , 179 , 181 , 245Starfish ,
bottom ,2 3 7 ,
240, 247
Starfish , larva ,1 84 , 186
preservation , 3 75Steam hau linggear , 266- 2 7 1
Sten orhyn chu s (seal ) , 406Stor
8
natop oda of p lan kton ,1 80
1 2
Stom iatida , 3 2 1
Storage bottles for
sam p les , 3 3of sp ec im en s
,2 8 7 ,
2 88, 3 6 1
3 67Storm s , 9 - 1 1
Stream curren ts , 5 7Sty liola , 185Sty losp ira , 166Sublittoral region ,
1 28,1 29
Subsiden ce , 67-69 , 9 6 , 9 7
Sun light , p en etration of water ,
3 2
S un p illar , 24Surface sam p les of water , 3 4 , 5 1
Surging'
of barom eter ,1 3 , 1 4
Swabs or tangles , 70, 7 1 ,2 9 1
Syllida , 1 75
Tahiti , 84Tangles or swabs , 70, 7 1 ,
2 9 1
Tan ks for storage , 1 1 1 , 2 87 , 2 88
Taou ia , 1 43Telegraph cables , an im als on
265Teleostei (bony fishes) ,
eggs , 3 1 6 , 3 17Tem ora , 177Tem p erature , air , 1 1 , 1 2 , 22
deep-sea ,
262
effect on p lan ts ,1 3 1 ,
1 3 2
on an im als , 1 9 1- 1 9 3 ,
2 5 2water , 3 1 , 3 2 , 62
Terebratu la , 259Terr igen ou s dep osits , 2 10, 2 1 3 ,
224- 2 26
Textu laria , 8 1
Thalassicolla , 1 64Thallu s ,
1 2 7Therm ograph , 1 6
Therm om eter , air ,1 5
- 1 7water , 3 5-
3 7c orrection s for , 42 , 43 ,
46
errors , 3 5 , 3 6 , 44. 46 , 49in su lating, 50
INDEX
Therm om eter ,wa ter , m axim um
and m in im um, 45 , 49 ,
2 9 7 n .
reve rsing, 42-
48 , 45Therm om etric scale conversion ,
4 1 9 , 420
Therm ostat , 5 3Thia larva , 181Tide
,e ffect on shore an im als ,
66
on shore p lan ts , 1 30
gauges , 64Tom opteris , 1 75 , 176Tornado , 9Tow n et , c losing,
1 9 2 ,1 9 5
on dredge , 2 9 1
on trawl , 29 8op en , 1 88- 1 90,
1 9 3standard , 1 9 4 ,
1 9 5 , 1 9 9treatm ent , 1 5 5 ,
1 89Traces for fishing lin es , 3 2 7 , 328Trade winds , 7Tramm el n et , 3 36-
3 3 8
Trawl , Agassiz , 296, 301 -
302beam , 29 5-
301 ,
m idwater , 3 4 1 , 3 42otter , 302
-
305Trawling, 29 5
-
305deep
-sea , 2 7 1-2 7 7
shallow, 2 80-2 8 1
sorting catch , 285 , 286
Trem atoda , p reservation , 3 78 ,
3 79Trep angs ,
22 7 ,240, 243
collection , 74 , 100larva ,1 84 , 186
preservation , 3 76
Trichechida , 406 , 407Trichodesm ium , 123 ,
1 2 4Trichogyn e , 1 5 o
Trochamm ina , 8 1
Trop ical outfit , 1 05 - 1 1 2,1 56
Tu ck se in e . See Se in eTun icata . See UrochordataTurb inaria ,
1 43Tuscarora , 167Typhoon ,
10
Udothea ,1 3 5 , 139Ulva , 1 26 ,1 3 5 , 136
Upwelling,am ovem en t of deep erwater to or towards thesurface
cause of, 62
45 1
Upwelling,e ffect on atm os
pheric tem p erature ,1 2
Uro chordata , 1 84 , 2 49 , 2 5 1
p reservation , 3 8 1
Urospora ,1 3 5
Vanvoorstia , 1 26Velella , 173 , 1 74 , 3 7 3Ve liger larva ,1 82 , 185
Vertebralina,8 1
Vo lcan ic dep osits , 2 1 0, 2 1 1islands , 83 ,208
m ud , 2 1 3 , 22 5Vo lcanoes , subm arin e,103
Walru s , 406 , 407Water
, Chap ter I I 26-64bottle ,how to work , 50, 5 1in su lating, 3 7
-
42
K ofoid’
s,for water?and
p lan kton ,1 1 6
reversing, 42 n ., 48bucket for sam p les , 3 4
chem ical and physical work ,5 2
com position , 29
general circu lation , 5 7- 64
observation s n eeded , 28
source of bottom , 62
storage bottles for sam p les ,3 3 , 3 4
tem p erature , 3 1 , 3 2
un iform c ondition s at greatdep ths , 2 7
Watersp out , 9 , 2 3Waves , angle of wind im pact, 22
he ight m easurable by barom eter , 1 5
Waxing corks an d stop p ers , 2 88
Weather , effect on floating an i
m als ,1 9 5
on shore an im als , 65 , 66
scale , 42 2
Whales , 3 83-
402
ear -bon es in dep osits ,2 1 4
Whaling station s an d 1 eturn s
White whale , 3 89 , 3 9 9Wilem oesia , 256W in ch , steam , 269W ind , 5
-
9angle of im pact , 2 2deviation of, 5
452 INDEX
W ind observation s , 1 7sc ale , 422
Wire rop e ,dredging and trawling, 2 7 1 -2 74
greasing, 2 77 , 2 79soun ding, 2 7 7 , 2 78
tow n ets ,1 9 0, 2 79water bottles , 50, 201
Worm s ,o f p lan kton ,
1 7 5shore c o lle ction , 7 7See also Cha top o da ,
etc .
Wyville Thom son R idge , 208 n .
Yacht deep -sea work , 2 7 1 - 2 80
Equ ipm ent , Chap ter V I I I266-2 88
THE END
' Yacht hand ling, 29 2- 29 5 ,
laboratory , etc 283-28
shallow work, 2 80- 2 83
steam hau lage , 266-2 7 1
Young fi sh n et, 3 4 1 , 342
Y ngel- trawl , 3 4 1 , 342
Zalophus , 408
Zeuglodon , 4 1 4Ziphio id whale s , 3 9 8 , 3 99Zoéa larva , 1 82
Zoological station s , 423-
429Zoop lan kton . See An imfloatingZostera , 1 26
‘HIn 1 85 7 Negre tti and Zambra first c on struc tedthe Deep
- sea Thermometer upon S ix’
s p rinc ip le( n ow te rm ed the M iller ”
typ e ) , which was p rovedcapable o f resisting great p ressure .
In 1 878 they p roduced and paten ted the“ R eversing”
pattern ,which m ay be supp lied
in Magn aghi or S co ttish fram es .
(_HS in c e that tim e m any im p rovem en ts have been
embodied,
and their m o st rec en t D eep -sea
Therm om e te rs p rovide a very op en range ,enabling
much finer readings to be observed, are fitted withan auxiliary therm om eter
,have the capac ity
de term in ed ,e tc .
Q1] A de sc rip tive p am phlet, and p rice listso f an y other in strum en ts , will be gladlyforwarded p ost free on request.
NEGRETTI 85 ZAMBRAM akers o f Oceanographical , M e teorological ,Optical , Nau tical , and S urveying In strum en ts .
H o lbo rn Viaduc t,London
,E .C .
B ran che s : 45 C ornhill , B O ; 1 2 2,R egen t S t.
,W .
In “ Magnaghi fram
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M ICROSCOPY ,The Con struction ,
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