REPTILIAN TAPEWORMS. 35 



pointed out that in his opinion the reptile Ichthyotaeniids do 

 agree together and differ from the fish Ichthyotaeniids in a number 

 of points which he enumerates. 



Schwarz comes to the conclusion that the reptilian Ichthyo- 

 taeniids form a group which is characterised by the peculiar spiny- 

 outgrowths of the egg-shell, by the fine spines upon the rostelium, 

 by the complicated coil of vas deferens and the protrusible cirrus- 

 sac, and finally by the arrangements of the transvei'se muscles. 



It does not appear to me that all of these features are distinctive 

 of the reptilian Ichthyotaeniids ; for the coiled vas deferens is 

 found in other species of Ichthyoicenia not from reptiles ; the 

 fine spines upon the rostelium and early segments of the body are 

 at least not to be found in the species from the Cobra w-hich I 

 describe in the present papei\ The peculiar and delicate spines 

 which deck the egg-shell are figured and described by Schwarz 

 only in /. nattereri. The cirrus-sac does not seem to be protru- 

 sible in the way which he figures it, in the species of Iclitliyo- 

 tcenia which I have described in the present paper from various 

 species of Varamts. These characters are, in fact, not sufficiently 

 general or not sufficiently distinctive to form a group. It must 

 be admitted, however, that tSchwarz suggests no name for his 

 group, and thus does not unduly emphasize it. 



It appeal's to me, on the other hand, that we can separate off as 

 a distinct group of generic rank the species of Ichthyotcenia which 

 inhabit, not reptiles generally, but the lizard genus Vara7ius 

 only. And if so, we must obviously term this genus AcanthotcBnia, 

 adopting v, Linstow's name. The genus will be chiefly distin- 

 guished by the fine spiny covering of the scolex'and anterior 

 segments, and, as I think, also by the character of the longitudinal 

 muscular layer. I am disposed to think that, as I have described 

 in several species in the present paper, the internal layer of 

 longitudinal fibres is found only in the anterior region of the 

 body. A third character is perhaps afforded by the com- 

 paratively large size of the rostellar region, which is apt to be 

 insignificant in the snake Ichthyotaeniids. Further than this I 

 do not think we can go at present, I propose the name of 

 'OphidoUenia for a new genus to include at any rate the species 

 'which I describe in the present paper from the Indian Cobra. 

 Its most salient anatomical character is of course afforded by the 

 structure of the utei-us and by the ventrally and medianly placed 

 external orifices of the same. 



This genus Ojihidotce-nia also contrasts with Acanthotcenia in 

 the lack of internal longitudinal muscles antei'iorly and in their 

 presence posteriorly. The inconspicuous rostellar region affords 

 another distinguishing mark. Tn all of these characters, with the 

 possible exception of those offered by the uterus, this genus agrees 

 with other snake Ichthyotaeniids, We cannot, therefore, as yet 

 attempt to fix the limits of this genus Ophidotcenia, in fact not 

 until the structure of the uterus has been I'einvestigated in other 

 Ichthyotaeniids in the light of my own discovery recorded here. 



3* 



