1874.] W. Theobald — On Indian and Bicrmese species of Trionyx, 79 



a well-marked median ridge. This point will alone suffice to discriminate 

 the two species without a description of the soft parts, which I have no 

 materials for giving. I of course do not regard it yet as satisfactorily esta- 

 blished, that, according to Dr. Anderson, every ocellated Trionyx in Bengal 

 belongs to this species, but should this fact he established, it will form an 

 external mark for diagnosing between young individuals. 



The third species of this paper is Tr. stellatus, Geoff. 



I have myself a single specimen procured at Moulmein, of which I give 

 a figure reduced to one-third of the natural size, and figures of the head of the 

 full natural size. This species possesses none of the dark marks on the head 

 seen in Tr. gangeticus, or described by Griinther as met with in Tr. javani- 

 cus, though that author cautiously adds : — " The characteristic markings of 

 the head of the continental specimens are not mentioned in descriptions of 

 Javan individuals, so that both may be specifically different." — GuntJiers 

 Reptiles^ Br. India, p. 48. 



The plates of the species here given may enable others to determine the 

 species more satisfactorily, but as far as the materials and books of reference 

 at my command enable me to judge, I am inclined to refer it to Tr. stellatus^ 

 Greoff,, a head of which is figured in the Fauna Japonica, published in 1833. 



Te. Stellattjs, var Javan, Geoff".^ S. H. Siebold, Faun. Jap. Chel. 

 Tab V. f. 6. 



Tr. javanicus, Schw., apud Gitnfher, in part, not Tr. Javanicus, Gray. 



Tr. peguensis, Gray, Supp. Cat. S. R.,p. 90. 



Tr, Jiurum, Gray, Ann. Mag. JSf. H., 1872, p. 360, as Tr. Bhayrei. 



Skull of an adult;' apud Gray, F. Z. S., 1869,^. 217. 



" Leih-hwaf of the Burmese. 



I was at first much inclined to unite this species with the last, but they 

 are, I am convinced, distinct, as all other diff"erences apart, the shape of the 

 head and the mandibular ridge in the one being represented by a mandibular 

 furrow in the other, are characters sufficient to establish their distinctness. 

 The dorsal disk too of Tr. Buchanani, Th., would seem to be much smoother 

 than in Tr. stellatus, and less furnished with tubercles or warts, (if furnished 

 at all) a point that can hardly be judged from a half grown and fully adult 

 specimen. 



The skull mentioned without name in the Proceedings of Zoological 

 Society, and subsequently described by Dr. Gray as Tr, peguensis, belonged 

 to an animal taken by a fish hook from the Sittoung river at Tonghoo, and 

 has probably outgrown the spotted stage figured in the Fauna Japonica. 

 During life, the Moulmein specimen displayed yellow-coloured spots, but the 

 yellow gradually fades after immersion in spirit, and hence is not mentioned 

 in descriptions, or rather described as white. 



I now come to the consideration of a species which would seem to be 



