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COLLEGE ZOOLOGY 



The classes of annelids are as follows: 



(1) Class Archiannelida. Marine worms without setae or 

 parapodia. There is only one family, including two genera. 

 Example: Polygordius (Fig. 162). 



(2) Class Chaetopoda. Marine, fresh-water, or terrestrial 

 worms with setae and a perivisceral ccelom ; often divided by 

 septa. Examples: Lumbricus (Fig. 154), Nereis (Fig. 163). 



(3) Class Hirudinea. Marine, fresh-water, or terrestrial 

 worms without setae or parapodia. Anterior and posterior 

 suckers are present. Examples: Hirudo (Fig. 169), Clepsine 

 (Fig. 171). 



3. CLASS I. ARCHIANNELIDA 



A single family, POLYGORDIID^E, belongs to this class; it 

 includes two genera, Polygordius (Fig. 162, A) and Protodrilus. 



e \J-ct. 



k 



FIG. 162. Polygordius appendiculalus. A, dorsal view. an, anus; 

 ct., cephalic tentacles; A, head. B, trochosphere larva, an, anus; e, eye-spot; 

 m., mouth. C and D, stages in development of trochosphere into the worm. 

 Pnp, pronephridium. (From Bourne, after Fraipont.) 



