240 Dr. W. p.. Bciiliam on an 



in 7?. 'paradoxus tliey occur on somites xix., xx., and xxi. 

 In B. GuUehnus tlie clitellum occupies almost the same 

 somitos as in the present species, viz. xv. to xxv., the tuber- 

 cula liave an identical position, and the same difference in 

 regard to the ventral limit of the clitellum is noted and figured 

 \>y Beddard for that species. 



The iiephridiopores^ as in other species, are in line with 

 the outer (lateral) couple of chsetse, the first pair being on 

 somite iv. 



The male pores were quite evident heticeen the somites 

 xix./xx., in a line with the second chaita on each side. Tiiis 

 is the position assigned to these pores by Perrier. Neither 

 Horst nor Beddard succeeded in detecting them ; but in a 

 specimen of R. Guh'elmus which I possess 1 find them to lie 

 between somites xx./xxi. I could not detect any other 

 genital pores on the surface. 



There are no dorsal pores. 



Internal Anatomy. 



There is a groat displacement of the internal organs, owing 

 to the iniiindibulate nature of the septa, so that the organs 

 appear to lie in somites considerably posterior to those to 

 which they aclually belong. 



None of the septa are strong ; in fact they are all particularly 

 thin and trans])arcnt, and are therefore difhcult to trace, for they 

 overla]) one another and allow the organs below them to be 

 seen. But it' the sejjta fail us inapjiortioning the organs to their 

 true morphological position in the body, we have an excellent 

 guide in the nephridia, which, as Horst noticed in his species, 

 are very conspicuous ; and by following them to their 

 external pores 1 was able to determine the real somites to 

 w hieh the various otiier organs belong. Tiiese nephridia^ as 

 Beddard found in //. GuUdmus and is frequently the case in 

 other genera *, differ in their size and shape *Jcc, in different 

 regions of the body. 



The first pair, or "peptonephridia" as 1 have called them*, 

 differs from the rest both in the greater length of the convo- 

 luted tube (PI. X. fig. 4) and its more glandular appearance, 

 and in the fact that the duct C(»i<»itinicutes icith the (jut and 

 not with the exterior. The convoluted tube, forming a bilobeil 

 glandular-looking mass, lies about halfway along the ceso- 

 ]>hagus (fig. 2, )i't.) at its side ; from it the large muscular 

 duct passes for\^ ards and downwards, soon coming to lie 



* Benham, "An Atteiiipl tn t'liis.-ity I'^iutliwoniis." (jliinit. Jomii. 

 !Micr. Sfi. x\.\i. p. I'li*. 



