216 



ZOOLOGY. 



feet are jointed, thus anticipating tlie Jointed ajipendages of 

 the C'rustacea and Insects. 



The Aiinelidcs are divided into two suborders. The first 

 suborder, OU[iuchceta, comprises Lumbricus, Nais, etc., while 

 the second suborder, Cliwtopoda, embraces Syllis, Auialytus, 

 Xereis, Polydora, Aphrodite, and Polyno'e, which are free- 

 swimming, while the tubicolous worms which respire by spe- 





Fig. 152. 



Fig. 152. — Cistenides Gouldii, and its tub«. — After Verrill. 

 Fig. 153 — Euchone eUgans, enlai*ged. — After Verrill. 



cial branchiae, or gills, on the head, live in tubes of sand or 

 in limestone shells. Those which live in sand or nnul-tubes 

 are Cirratulus (Fig. 154), Clymene and Clynwnella (Fig. 150), 

 which has no branchiae, Amphitriie (Fig. 151), Terelrella, 

 Cistenides (Fig. 152), Sabella, and Eudione (Fig. 153), 

 while Protula, Filograna, Seijiula, and SpirorMs secrete 

 more or less coiled limestone tubes. The large solid shells 

 of the Serpulse assist materially in building up coral reefs. 



