304 W. B. BENHAM. 



Fig. 23. — Diachseta. a, b. Genital and alimentary sys- 

 tems, sp. Sperraatheca. g. Gizzard, s. Commencement of 

 acculated intestine. Modified from my own figures in ' Quart. 

 Journ. Micr. Sci./ xxvii. n. The normal nephridia commencej 

 as in Urochseta, immediately behind the extra-buccal pepto- 

 nephridium (epn.). c. Somites xxi, xxii, xxiii^ seen exter- 

 nally, showing the alternation of the setae with exception of 

 No. 1 on each side, the position of the nephridiopores (rings), 

 and of the spermiducal pores, which are represented as black 

 dots. 



Distribution : St. Thomas, West Indies. 



Family VIII. — Rhinodrilid^. 



Fig. 24. — Rhinodrilus. a, b. Genital and alimentary 

 systems and nephridia. Composed from my own observations 

 on, and from Beddard's description of, H. (Thamnodrilus) 

 gulielmus, ^ Proc. Zool. Soc./ 1887, p. 154. Following the 

 greatly modified first or extra-buccal pepto-nephridium (epn.) 

 are seven pairs of nephridia (n.) which diflFer from the more 

 posterior ones (n.^) in Somite x in having no csecal prolon- 

 gation of the duct. C(E. The caecum of the posterior nephridia. 

 SP. Spermathecse. g. Gizzard, ca. The first calciferous diver- 

 ticulum, s. Commencement of the sacculated intestine, c. 

 External view of Somites xix, xx, and xxi, to show setae, 

 nephridiopores, and intersegmental spermiducal pores. 



Distribution : North of South America. 



