phylum annelida

Vermiform

worm shaped body 

Metamerism

repetition of body segments

Homonomous segments

segments nearly identical in structure

Setae (Chaetae)

bristle like structures for movement

Parapodia

paired lateral appendages for locomotion

Closed circulation

blood enclosed in vessels 

Metanephridia

excretory organs

Trochophore larva

free swimming larval stage 

Class Polychaeta –

has many setae, marine worms with well-developed heads

Class Oligochaeta –

has few setae, has clitellum, respiration by diffusion

Class Hirudinea –

mostly parasitic, lack setae, open circulation, clitellum present

Class Polychaeta examples

sandworm, tubeworm, fireworm

Class Oligochaeta example

earthworms

Class Hirudinea example

leeches