Platyhelminthes, Nematoda, Annelida

Phylum Platyhelminthes

• Flatworms - Dorsoventrally flattened (top to bottom)

• Digestive tract has one opening (incomplete)• Simple nervous system• No true circulatory or respiratory systems

Planaria

PlanariaRegeneration

Lined Flatworm

Tapeworm

parasitic

Tapeworm

Tapeworm in a Carp

Tapeworm

Tapeworms in dogs &

cats

Flea larvae

Flukes

Phylum Nematoda

• Long, tapered, cylindrical shape

• Longitudinal muscles

Phylum Nematoda

• Long, tapered, cylindrical shape• Longitudinal muscles• Complete Digestive system• No circulatory or respiratory systems

Roundworms

Parasitic Nematodes

Hookworms

Roundworm Life Cycle

Phylum Annelida

• Segmented worms• Coelom (body

cavity)• Circular muscles• Circulatory system

(closed system)

Class Polychaeta

• “many bristles”

Bristle Worm

Christmas Tree Worm

Star Horseshoe

Worm

Plume Worm

Social Feather Duster Worms

Medusa Worm

Class Oligochaeta“few bristles”

Earthworm Movement

Earthworms Mating

Class Hirudinea• No bristles

Leech’s Mouth