1912.] N. ANNANDALE: The Indian Mud-Turtles. 155 
An examination of the fine collection accumulated in this 
museum by the late Dr. John Anderson renders it necessary 
to reinstate one species (7. nigricans) inadequately described by 
him and since ignored by most writers on the Chelonia. All the 
recognized Indian and Burmese species are represented in the 
Indian Museum, but T. /eithii and T. cartilagineus only by young 
specimens. We possess the types of the following described 
species :— 
T. buchanani, Theobald. (=T. hurum, Gray). No. 1090 
(skeleton). Proc. As. Soc. Bengal, 1874, p. 78. 
T. nigricans, Anderson. Nos. 1898 and 735 (skeletons). 
Ann. Mag. Nat. Hist., (4) XVI, 284 (1875). 
Mr. Boulenger suggests in his “‘ Catalogue of the Chelonians, 
etc. in the British Museum” (p. 243) that at least some species 
of Tytonyx are dimorphic, the two phases differing in the form 
and structure of the jaw and their characteristic features being 
produced, in the case of the individual, by the method of obtain- 
ing food adopted at an early age. 
So far as the Gangetic species are concerned I have been 
unable to obtain any evidence that this is so. Two distinct 
species, the skulls of which are different at all ages, occur together, 
namely T. gangeticus and T. hurum. The former has a blunt, 
the latter a sharp snout; and the youngest skulls can be 
distinguished with ease by the length of the symphysis of 
the lower jaw. I have examined many hundreds of living in- 
dividuals, as well as a large series of skulls, and have never 
come across a specimen that was in any way intermediate 
between the two species in structure; while only one specimen of 
T. hurum (No. 16627) had some resemblance to T. gangeticus 
in colour, or rather differed so widely in this respect from normal 
individuals of its own species that its superficial appearance was 
reminiscent of 7. gangeticus, although it lacked the characteristic 
head-markings of that species. 
A not uncommon abnormality in the Indian species is an 
upward curvature of the vertebral column that results in the 
carapace, instead of being flat, assuming a conical form and 
actually in some instances being deeper than it is broad. The 
presence of a deep groove on the middle line of the carapace 
is another common abnormality. 
The nature of the food of the members of the genus is 
apparently a disputed point. So far as my own observations 
go, they are practically omnivorous, at any rate when living 
in a semi-domesticated state. In the Malay Peninsula certain in- 
dividuals (probably of T. cartilagineus) haunt rivers in the vicinity 
of villages and act as scavengers. The specimens of 7. formosus 
that are kept in the Arrakan Pagoda at Mandalay feed readily 
on curry and rice and those of (?) 7. Aurum that live in some- 
what similar conditions in a tank attached to one of the temples at 
