NEW TAPEWORMS FROM THE HTRAX, 579 



the present species a good deal of the head lying between the 

 suckers is occupied by the coils of water-tubes, which approach 

 very neai-ly to the external surface at the apex of the head. 

 These tubes ai-e not in any way irregularly dilated, but theii- 

 diameter throughout is rather greater than that of the tubes in 

 the immediately following neck-region of the body. Janicki is 

 not disposed to lay great weight upon the absence or presence of 

 a neck in these tapeworms. In the present form the strobili- 

 sations begin very close to the head, which is supported by a 

 segment bioadening toAvards the head, which may be regarded as 

 the neck. In the accompanying text-figure (text-fig. 72) will be 

 seen the general characters of the strobila of this worm. 



The body-wall of the worm is relatively thick, but here the 

 cortical layer is not so definitely marked off from the medullary 

 parenchyma as is so often the case. The absence of a strong de- 

 limitation is due to the very feeble development of the transverse 

 musculature, which is generally hardly, or not at all, recognisable 

 in transverse sections. Another reason which renders the two 

 layers more uniform in this species than in my Thysanotmnia 

 gamhiana and in the species of Hyracotcenia described in the 

 present paper, is that there are stout muscular fibres in the 

 medullary parenchyma comparable in thickness to the longitu- 

 dinal muscular fibres of the coitical layer. 



Water Vascular Tubes. — These tubes are, as usual, two on each 

 side. They lie, as a rule, almost parallel with each other, the 

 smaller dorsal tube having, however, an inclination to the dorsal 

 side which is more or less pronounced as the case may be. The 

 more medianly situate ventral tube is the wider, but the difierence 

 between the two is not perhaps quite so well-marked as in 

 Thysanotmnia gamhiana. The two vessels are not united across the 

 proglottids by a regular series of transverse vessels, one to each 

 proglottid, but, as in other species of this genus and in Thysano- 

 tcenia gamhiana, are united by a network of tubes found all ovei- 

 the segments. I did not follow out into any detail the precise 

 arrangement of the branching connecting-tubes. 



The ovary, when fully mature, appeal's to be definitely a single 

 body lying anterior to and in contact with the vitelline gland . 

 The latter lies on a level with the groujj of testes of the pore side. 

 The ovary lies, when less fully mature, entirely to the median 

 side of the two water vascular tubes. Later on, it appears to 

 extend somewhat and is larger actually, and considerably larger 

 relatively, than I found it to be in Thysanotcenia gamhiana. 

 The ovary is clearly also larger in the present species than in 

 Inermicapsifer hyracis, according to Janicki's figures. In the 

 later stages of the ovary, when it is gorged with ripe eggs and 

 these are beginning to spread through the proglottid, a peculiarity 

 of structvire, perfectly plain in earlier stages, is not ob^dous. 

 One such example, representing the ovaries, is represented in 

 text-figs. 73 and 74. It will be there seen that the ovary really 

 consists of clumps of rips and unripe eggs situated at the ends of 



