ROLL CALL y , 



PHYLUM I X — ANNELIDA — Segmented worms. 



Characteristics : Segmented animals bearing distinct head, digestive tube, 

 coelom, and sometimes nonjointed appendages; frequently supplied with 

 chitinous bristles (setae) ; 6500 species. 



Class I — Archiannelida — (Polygordius). 



Characteristics : Marine worms lacking setae or parapodia ; trochophore 

 larvae present. 



Class II — Chaetopoda — Clam worms, tube worms, earthworms (Nereis, 

 Glycera, Chaetopierus, Lumbricus). 

 Characteristics : Members of this class marine, terrestrial, or fresh water ; 

 paired setae characteristically arranged in integumentary pits or upon 

 parapodia ; further subdivision based upon number of setae present : 

 Oligochaeta, a few ; Polychaeta, many. 



Class III — Hirudinea — Leeches (Hirudo, Glossiphonia). 



Characteristics : Hermaphroditic, dorso-ventrally flattened annelids with 

 32 body segments, two suckers, one surrounding mouth, the other the 

 posterior end ; setae and parapodia absent ; growth of mesenchyniatous 

 cells reduces coelom. 



Class IV — Gephyrea — Sipunculid worms (Phascolosoma). 



Characteristics : Non-segmented when adult, without setae or parapodia ; 

 characterized by a large coelom and trochophore larvae. 



Class V — Chaetognatha — Arrow worms (Sagitta). 



Characteristics: Small, transparent, marine invertebrates with well- 

 developed body cavity, alimentary canal, nervous system, two eyes; 

 lobes on sides of mouth armed with bristles which aid in capturing food. 



