482 



ZOOLOGY 



SECT. 



condition it enters the pharynx of the female and when sexually 

 mature establishes itself permanently in the nephridium. 



Pseudobonellia is nearly related to Bonellia, but has two anterior 



neph.fun 



ant.neph 



QV 



post.neph. 



FIG. 397. Bonellia, general view of the internal organs. 

 an. anus ; ant. neph. anterior nephridium:; int. intestine ; 

 FIG. 396. Bonellia viridis, entire neph. fun. nephrostome ; ces. oesophagus ; ov. ovary ; 

 animal (female) with the proboscis ph. pharynx ; post. neph. posterior nephridium ; prob. 

 moderately extended. (After Greef.) proboscis; rent. ress. ventral vessel. (After Greef.) 



nephridia (uteri). The degenerate male, which Kas no setae, lies in 

 a median pit opening on the ventral surface between the two uteri. 

 Hamingia has a general resemblance as regards the female to 

 Thalassema, but there are no setae. There are two anterior 

 nephridia." The male, which has two setae, is 

 degenerate and parasitic in the female, as in 

 Bonellia. 



Acanthohamingia has eight small setae. 

 Epithetosoma has an extremely long filiform 

 proboscis which, unlike that of the other 

 genera, is hollow, containing a prolongation 

 of the coelome. There are no setae. There is 

 a single nephridium and no anal vesicles. 



In Saccosoma both proboscis and setae 

 appear to be absent. The male is not known. 



r il ml , r -n i 



Development. - - The larva of Echmrus 

 (Fig. 400) has a well - developed pre-oral 



FIG. 398. One of the cili- 



ated funnels of the poste- 



