new Genus of Oligoclioita. 85 



the male pores of some Euclrillds ; and one's first idea about 

 an earthworm coming from tropical Africa is that it must be- 

 long to that family. The microscopical examination of this 

 area shows that it is quite unlike anything that occurs in the 

 Eudrilid^e ; it is much more like what we find in Benhamia\ 

 and Gordiodrilus should possibly be referred to the same 

 family, ^'. e. the Acanthodrilidfe. The male genital pores arc, 

 as in the other species of this genus, three on each side ; two 

 pairs of atrial pores, and one pair of apertures separate from 

 the atrial pores by which the vasa deferentia open on to the 

 exterior. These pores are situated on the ridge itself, and 

 not on the area which it bounds. The position of the pores 

 is shown in fig. 1. Gordiodrilus 7-obustus is to be dis- 

 tinguished from G. elegans no less than from G. tenuis by 

 the presence of copulatory papilla3 upon segment xix. I 

 could find no trace of such papillfe in the present species. 

 Possibly their absence is to be explained by the strongly 

 developed ridge which I have just described ; the sucker-like 

 structure which is thus formed may be sufficient to cause the 

 worms to adhere together during copulation, and render un- 

 necessary any special papillae performing the same function. 



The sette of the present species are strictly paired and 

 ventral in position. There is no difference in size between 

 the seta3 of the dorsal and lateral couples, nor are there any 

 particular segments upon which the setae are enlarged ; in 

 these points Gordiodrilus elegans differs from both its con- 

 geners. Furthermore the ventral setse of segments xviii. and 

 xix. are absent in the fully mature worm, while these same 

 seta? are present in the other species. Neither are there any 

 special penial setae to take their place. The clitellura occu- 

 pies segments xiii.-xviii. ; it is only developed dorsally and 

 laterally ; ventrally there is an area left of which the epi- 

 thelium is unmodified. 



Internal Structure, 



In the anterior part of the body a number of the inter- 

 segmental septa are specially thickened ; the first of these is 

 that which divides segments v./vi. ; the last is between 

 segments ix./x. 



The vascular system appears to be chiefly remarkable for 

 the fact that there are only two large transverse vessels 

 uniting tiie ventral and dorsal trunks ; these lie in segments 

 X. and xi., and have distinctly muscular walls ; they are 

 very conspicuous in the living worm. 



The alimentary canal is, as has been already remarked, 



