64 MR, F. E. BEDDARD ON [Feb. 4, 



setae and the genital papillae ; and it is precisely these characters 

 which lead me to identify the present species, at least provisionally, 

 with Perichceta biserialis. 



The prostomium is small and does not divide the circumoral 

 segment. 



The setce form a continuous row round each segment ; on the 

 ventral side a single pair, one on either side of the median line, are 

 very much enlarged, being three or four times as large as the rest. 

 On the anterior segments of the body two or three setse on each 

 side are thus enlarged ; posteriorly there is only a single pair of 

 these setse. 



The cHtellum occupies segments 14-16 inclusive and is developed 

 all round the body. There are no setce on the clitellum '. 



The male generative pores are upon segment 18. 



The five succeeding segments each have a pair of genital papillce, 

 which are placed in positions exactly corresponding with the male 

 pores some distance on either side of the median line ; these papillae 

 as well as the male pores are situated just in front of the ring of 

 set* (Plate V. fig. 4). 



The oviducal pore is single and median upon the 14th segment. 



No spermathecal pores could be detected. 



Dorsal pores are present, but I am not able to state at which 

 segment they commence. 



Concerning the internal anatomy I am not able to say much, as 

 none of the specimens examined by me were in a sufficiently good 

 state of preservation for section-cutting. 



The nephridia show the usual characters which are found in the 

 genus Pericktvta ; they present a series of minute tufts attached to 

 the body-wall ; in some of the anterior segments they form immense 

 masses completely occupying the cavity of the segment. 



There are only three mesenteries which are specially thickened ; 

 these lie between segments 6-7, 7-8, 8-9 ; of these three mesenteries 

 the last two are considerably thicker than the first. 



The gizzard lies behind the last thick mesentery and occupies at 

 least two segments. 



The most remarkable fact about this species is that there are 

 apparently no spermathecae. 1 have only been able to examine two 

 specimens, and there was not the slightest indication of spermathecae 

 in either of these. I cannot of course state positively that these 

 structures are absent, which seems unlikely seeing tiiat in all other 

 species of Perichceta they are present ; but the fact remains that 

 they were undoubtedly absent in two examples, the only complete 

 examples which I possess ^. 



' The presence or absence of sets on the clitellum is characteristic of a given 

 species and should always be carefully noted. It serves, for example, to dis- 

 tinguish P. indica (where they are absent) from P. affinis (where they are pre- 

 sent). 



^ Since writing the above I have received Rosa's paper (27) in which he 

 refers to the absence of spermatheca in Lumhrkiis cuteni and AUolohoj^hora con- 

 strMa, besides Criodrilus, 



