NEW TAPEWORMS PROM THE HYRAX. 587 



exactly similar to those which have been described as continuous 

 with the prolonged oviduct, but not always continuous with it. 

 They would seem to be produced indepeiidently of the genexvative 

 ducts. A network arrangement often characterised these regions 

 of the medullary parenchyma. This condition of the uterus 

 characterised proglottids in the same stage of evolution as those 

 which in Thysanotcenia gambiana possessed an uterus with a distinct 

 lumen. But if we are to compare them with earlier proglottids in 

 Thysanotcenia, then it must be remarked that in the present 

 species of Inermicapsifer there is no such regular band of nuclei 

 marking out the future uterus, as exists in the former worm! 

 The appearance is, in fact, totally different. In Inermicapsifer 

 the suggestion is merely of a crowding together in a quite 

 irregular fashion and a local multiplication of the nuclei of the 

 cells of the medullary parenchyma. In Thysanotcenia the nuclei 

 are in orderly arrangement and regular sequence, obviously 

 belonging to an organ which, as already pointed out, swells at 

 its medianly situate end into an oval region of greater diameter. 

 In Thysanotmnia we have obviously a regular outgrowth of the 

 generative system ; in my species of Inermicapsifer what would 

 appear to be a condensation of parenchymal tissue in contact 

 with and continuing on a very short, and in this species hollow, 

 outgrowth of the generative duct. I am not clear whether the 

 species described by Janicki agrees most nearly with the species 

 described in the present paper or with Thysanotcenia gamUana. 

 I am disposed to think that the branched strand in which the 

 slightly prolonged oviduct ends in this Inermicapsifer is not the 

 homologue of the solid mass of cells in Thysanotoinia gambiana, 

 which aftei^wards becomes hollowed out to form the uterus 

 of that worm ; in this case Inermicapsifer hyracis agrees more 

 closely with Thysanotcenia gambiana than with the species 

 described here. 



It might possibly be held that this network, which permeates 

 the segment when seen in horizontal section, is merely a stage 

 subsequent to that figured by Janicki in a proglottid of some- 

 where near the same stage of maturity as that which I am now 

 considering in the species of Inermicapsifer studied by myself— 

 that the lumen had, in fact, existed and had disappeared. That 

 this is not the case is clear from the fact that in this stao-e there 

 were not any ova contained in the meshwork, and in*' fact no 

 ripe ova anywhere outside of the ovary. The meshwork formed 

 by condensation of the parenchyma, in fact, precedes the extrusion 

 of ova from the ovary. Still, it may represent the imperfect 

 remains of a retiform uterus such as is characteristic of the o-enus 

 Dipylidium or, better perhaps, in relation to the present g^enus, 

 the Anoplocephalid genus Andrya. 



I have also been able to approach the question of the identity 

 or non-identity of the cavity in which the eggs lie with the 

 cavity of the uterus from another side. Text-fig. 77 represents 

 portions of horizontal sections through a proglottid in which the 



39* 



