REPTILIAK TAPEWORMS. 25 



termed a vesicula seminalis appears to be distinctive of /. gracilis, 

 and thus contributes largely to the establishment of its distinct- 

 ness as a species. 



This latter character also precludes the possible identification of 

 I. gracilis with either of the two species described by v. Ratz, 

 from which both /. gracilis and /. varia differ also in other 

 particulars. In /. hiroi the genital pore lies in front of the 

 middle of the segment instead of behind it, the neck is long, and 

 the progiottids, even posteriorly, are not plainly separable to the 

 eye ; the water- vascular tube is single on each side. It is therefore 

 not identical with either of my species. In /. saccifera the 

 positions of male and female pores alternate as in /. gracilis ; but 

 the cirrus-sac is described as round, as opposed, I presume, to oval, 

 which is its shape in /. gracilis, in which species, moreover, the 

 progiottids are longer ; but the two species are obviously very 

 near to each other. 



Finally, I do not think that these species can be confused Avith 

 V. Linstow's Acanthotcenia sMpleyi from Varanus salvator, for it 

 is very minute, only 13 '8 mm. in length by •1--4 mm. in breadth ; 

 the segmentation is not marked ; the cirrus-sac lies behind the 

 vagina and is crescentic in shape. The author, however, seems 

 to have missed the marginally situated vitelline glands, since he 

 identifies as such what is, I think, certainly the ovary. The 

 description setting forth the characters of a new genus and a new 

 species is, however, a very brief one. 



§ An Ichthyotfeniid fro7n the Indian Cobra (ISTaia tripudians). 



OPHiDOTiENiA NAiM, gen. et sp. n. (See p. 35.) 



The genus is already known to exist in a good number of 

 snakes, of which a list was given by v. Linstow in 1907 * and by 

 Schwarz in the following year f. There are at most seven species 

 known from snakes, if we except Crepidobothritoin gerrardi% from 

 Boa, and regard it, mainly by reason of its horseshoe-shaped 

 suckers, as a distinct genus. I have now to describe a form 

 which occurs in a species of snake wdiich has not hitherto yielded 

 examples of the genus. I obtained at least three specimens 

 (there were three scolices) of an Ichthyotseniid from an Indian 

 Cobra which died in the Society's Gardens on April 18th, 1912. 

 The longest individual measured, after preservation in alcohol, 

 110 mm., and had a greatest breadth posteriorly of 1*5 mm. 



The anterior end of the body gradually narrows up to the small 

 scolex, which is, however, wider than the neck which ixximediately 

 ensues. In none of the specimens was the rostellum very con- 

 spicuous for its size and extension beyond the suckers. Indeed, 

 I found that in the specimen which I examined by means of 

 transverse sections there was no prolongation of the head at all 



* " Ilelmintlien von Java," Notes Leyd. Mus. xxxix. 1907-8, p. 85. 

 t " Die Iclithj'ota'iiieu der ReptilicMi, &c.," Inaug.-Diss. Univ. Basel, 1908. 

 X Baird, Proc. Zool. Soc. 1860, p. 4,16 ; MonticelH, Atti Soc. Nat. e Mat. Modena, 

 (4) i. 1899, p. 9. 



