236 



ZOOLOG 7. 



feet are jointed, thus anticipating the jointed appendages of 

 the Crustacea and Insects. 



The Annelides are divided into two suborders. The first 

 suborder, Oligochceta, comprises Lumbricus, Nais, etc., while 

 the second suborder, Chatopoda, embraces Syllis, Autolytus, 

 Nereis, Polydora, Aphrodite, and Polynoe, which are free- 

 swimming, while the tubiculous worms which respire by spe- 



FIG. 158. 



Fig 158 CMenides Gouldii, and its tube. After Verrill. 

 Fig! ^.Euchone elegans, enlarged. Alter Verrill. 



FIG. 159. 



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

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

 are Cirratulus (Fig. 160), ClymenewaA. Clymenella (Fig. 156), 

 which has no branchiae, AmpUtrite (Fig. 157), Terebrella, 

 Cistenides (Fig. 158), Sabella, and Euclione (Fig. 159), 

 while Protula, Filograna, Serpula and Spirorbis secrete 

 more or less coiled limestone tubes. The large solid shells 

 of the Serpulae assist materially in building up coral reefs, 



