NEW TAPEWORMS PROM THE HYRAX. 585 



cirrus sacs of the three tapeworms. That of Thijsanotcenia lemuris 

 differs from the other two by its larger size, the cirrus sac in the 

 two remaining species being of about the same size. The cirrus 

 sac of Thysanotcenia lemuris is, indeed, fully twice the size that it 

 is in the two other species. In the species which forms the 

 subject of the present communication the cirrus is very small 

 and limited to the neck part of the cirrus sac, than which it is 

 no longer. The same characteristics apply to Thysanotcenia 

 lemii,ris, only that as the cirrus sac itself is larger, the ciri'us also 

 is larger than that of the species with which I compare it. In 

 both of these species the rest of the cirrus sac is filled with the 

 sperm-duct, which is, in both, dilated to form a vesicula seminalis; 

 but in Thysanotcenia lemuris the dilatation fills the whole sac, 

 while in the other species it is coiled and thus fills the sac in a 

 different way. In the species Thysanotcenia gamhiana there is no 

 such conspicuous vesicula seminalis, but just after the entiy of 

 the sperm-duct into the cirrus sac it is dilated for a short space. 

 On the whole, it appears that the cirrus sac of the present species 

 is more like that of Thysanotcenia lemuris than of Th. gamhiana. 

 One of the principal differences which this species shows from 

 Thysanotcenia gamhiana is in the character of the uterus. As I 

 have already mentioned in the present paper, as well as in my 

 memoir dealing with that species, the uterus is very plain, first 

 as a solid cord and then a narrow tube with an obvious lumen. 

 An examination of a large number of sections of the species of 

 Inermicapsifer described here has shoAvn nothing exactly like the 

 uterus of Thysanotcenia gamhiana. Nor can I reconcile what I 

 have seen with the figures of Janicki's illustration of the uterus 

 of Inertnicapsifer hyracis. In the latter species the uterus is 

 fi.gured * in horizontal sections through the ripe proglottid as an 

 irregularly shaped sac with numerous projections and outpushings 

 of its lumen — as, for example, in the genus Tetrahothrium t. 

 It is shown, however J, to commence as a sinuous tubular 

 structure, which appears to me to resemble very much the uterus 

 as I have described it in Thysanotcenia gamhiana. Earlier still 

 than this a solid cord of cells issues from the generative mass 

 which again would appear to be exactly comparable to what I 

 have seen in Thysctnotcenia gamhiana. Janicki, however, com- 

 ments upon the remarkable fact that the formation of a lumen in 

 this cord begins, not where it would be expected to begin, at the 

 ovarian end, but towards the middle of the segment. It is here, 

 moreover, that in Thysanotcenia gcmnbiana the solid cord of cells, 

 which subsequently becomes the hollow uterus, widens out into a 

 club-shaped extremity ; but I am unable to confirm or differ from 

 Janicki in fixing the point at which the uterus begins to be 

 hollowed out to be coincident with this club-shaped extremity. 

 It seems, however, to be very likely. 



* Xioc. cit. pi. xii. fig. 13. 



t Spatlich, in Zool. Jahrb. Bd. 28 (1909). 



X Loc. cit. pi. xii. fig. 17, uf. 



Proc. Zool. Soc— 1912, No. XXXIX. 39 



