70 VERMES. 



Class V. Gephyrea. 



Unsegmented marine worms, more or less cylindrical in form. There 

 is a proboscis or the anterior end of the body is invaginable. Nervous 

 system of a circumcesophageal loop (sometimes with a brain) and a 

 ventral non-ganglionated cord. A large enterocoelic body-cavity, usually 

 communicating with the exterior by a small number of anterior nephridia. 

 Sexes separate. 



A r m a t a (Chsetif era), with a proboscis and two ventral setae. Anus 

 terminal. Echiurus. Thalassema. Bonellia viridis (dwarf planarian- 

 like male, parasitic in the female). 



Inerma (Achseta), with invaginable anterior end, and no seta?. 

 Sipunculus nudus. Phascolosoma vulgare. Priapulus. The two 

 first with dorsal anterior anus. 



See note on p. 39. 



