756 FRANK E. BEDDARD, 



JPerichfeta rokiKjo n. sp. 



Of this very well niarked new species there weie four examples 

 in the coUection; I dissected three of these. Even the external 

 characters sliow oiie iinportant difference froni the more typical mem- 

 bers of the genus. There was no visible trace of the usually con- 

 spicuous male generative pores upon the 18th segment. In all 

 Perichaitidie which I have had the opportunity of examining, or whose 

 structure*! know from published descriptions, these pores are ex- 

 ceedingly obvious, and not to he overlooked; it is only in immature 

 Worms that they are invisible ; as all of the four individuals in my 

 possession are provided with a fully developed clitellum, the apparent 

 absence of the male pores cannot be set down to sexual immaturity. 

 In other respects the external characters are not in any way 

 remarkable, as will be seen from the illustration (Fig. 1). Perichceta 

 rokugo is a stoutly built species, not long in proportion to its thickness. 

 One individual had a length of 4' ^ inches with a diameter of 6 mm.; 

 this worm was composed of exactly 100 segments. Appended are the 

 lengths and uumber of segments of the three other specimens : 



A 4,7,10. ... 84 



B 2,4 5 .... 67 



C 3 .... 89. 

 The colour (in alcohol) is a greenish-brown — the clitellum a 

 darker brown. 



The seta> form perfectly continuous lines , as in all the other 

 species of the genus Perichmta (s. s.), and are, as is also characteristic 

 of this genus, implanted upon a distinctly marked ridge. This ridge 

 is especially prominent upon the posterior segments of the body. The 

 apertures visible on the ventral surface of the body are shown in 

 Fig. 1. The only aperture that is at all conspicuous is the Single 

 median oviducal pore ; the actual orifice is very minute ; but it lies in 

 the centre of a grey-coloured area surrounded by a white ring, which 

 contrasts with the dark brown of the rest of the clitellum. The 

 spermathecal pores lie on the boundary lines between segments VI VII 

 and VII VIII. On the Vlllth segment, in front of the ring of set<e, 

 is a patch of modified integument, about 2 mm in length, which bears 

 a num])er of closely-set minute pores. 



The internal anatomy of this species is, with the exception of 

 one feature of importance, not remarkable in any way. The inter- 

 segmental septa have the arrangement which is usual in this genus, 



