328 R. Lydekker — On the Tortoises descrihed as Chaibassk. [No. 4, 



of the Assamese 0. tlieobaldi from the typical Bengal form, and also 

 whether there were good grounds for regarding Gkaihassia as entitled to 

 generic distinction. In attempting to decide these points, I had the 

 advantage of consulting with my friend Mr. G. A. Bouleuger, of the 

 British Museum, to whom all students of the Chelonia are so much 

 indebted for his recently published ' Catalogue '* of that order ; and, 

 a fter careful comparison and examination, we both came to the conclu- 

 Bi(m that Ghaibassia theobaldi was not separable from 0. tricarinata, and 

 also that the genus Ghaibassia itself was not a valid one. Having arriv- 

 ed at these conclusions, it seemed advisable to put them on record, and, 

 since the type of this so-called genus was first described in the ' Journal 

 of the Asiatic Society of Bengal,' it appeared most appropriate to bring 

 them to the notice of the same Society. 



The tortoise on which the genus Ghaibassia was subsequently found- 

 ed was originally described by Blythf under the name of Gciiriii >j<la Iricari- 

 uata upon the evidence of a specimen obtained from Chaibassa, in Chota 

 Nagpur, Lower Bengal. I have had no opportunity of examining the 

 type specimen, even if that still exists, but, since the above-mentioned 

 female shell from the neighbouring region of Sirguja in the same district 

 agrees in all respects with the description of the type, it may be safely 

 regarded as specifically the same. 



In founding the genus Ghaibassia, Mr. W. TheobaldJ appears to have 

 taken his description from the two specimens ali-eady alluded to as hav- 

 ing been obtained from the Naga Hills, which he regarded (and, as it 

 now appears, rightly) as identical with the so-called Geoemyda tricarinata. 

 These specimens showed that this tortoise differed from Geoemyda by 

 the pi'esence of a temporal or zygomatic arcade, and Mr. Theobald 

 accordingly defined his new genus as " habit of Geoemyda, but zygomatic 

 arch complete." In the coui-se of his description it is, however, inciden- 

 tally mentioned that Ghaibassia tricarinata may bo distinguished from 

 Nicoria (Melanochelys) trijuga by the brown instead of white colour of 

 the iris ; thereby implying a close similarity between the two forms. 

 A difference in the claws of the two species is also noticed. Having 

 thus incidentally mentioned the similarity of G. tricarinata and N. tri- 

 juga, it is very remarkable that Mr. Theobald should not have clearly 

 stated what he regarded as the generic distinction between the two, and 

 that the two forms were placed i-espectively in the so-called families 

 Testudinidte and Etnydidm, which have no real distinctive features, and 

 have therefore been united by Mr. Bonlenger. 



* Catalogue of the Chelonians, Ehyuclioeephaliaus, and Crooodilos in the British 

 MuBOXTOi: London, (1889). 



t J. A. S. B., vol. xxiv, p. 714 (1S56). % Cat. Kept. British India, p. G (1876). 



