1864. ] DR. J. E. GRAY ON THE TRIONYCHIDS. 91 
Prof. Owen, in the ‘ Catalogue of the Osteological Specimens in the 
Museum of the College of Surgeons,’ describes the skull on which 
this species is founded. It differs from the skull of the young spe- 
cimens of P. cantorii in the Museum collection from Malacca in 
being rather longer compared with its width; but then that may 
depend on the age of the specimen, for its size and the bones of 
the dorsal disk show that it belongs to a more adult specimen than 
the young one with which I was able to compare it. 
There is some doubt as to the skull in the College of Surgeons 
having been obtained from Australia, as I have never heard of any 
Mud-Tortoises being found in that country; and it is not unlikely 
that the specimen was obtained from Singapore, or if obtained 
from Australia may have been carried there. 
b. Skull elongate ; forehead shelving, much produced behind ; nose 
very short, convex ; alveolar edge of both jaws with a deep 
groove. 
CHITRA. 
Chitra, Gray, Cat. Tort. B.M. 49; Cat. Shield Rept. 70. 
The head elongate, depressed ; nose very short; eyes near the 
front margin ; forehead elongate, slightly convex, shelving. Skull 
elongate, ventricose, thin, light; the nose very short, convex ; or- 
bits very large, near the front margin; the forehead very much 
elongated, several times as long as the face, shelving, slightly con- 
vex (see Cat. Shield Reptiles, t. 41). Palate flat, concave in the 
centre; internal nostrils anterior, with only a very slight, very 
broad depression behind each of them; alveolar edge with a deep 
angular groove, concentric, with sharp outer edges. Lower jaw 
strong, with a deep angular alveolar groove, concentric with the 
sharp outer edges (see Gray, Cat. Shield Rept. B.M. t. 41). The 
first vertebral plate of the dorsal disk is rather broad and transverse, 
arched in front; but (in the younger specimen at least) it is not so 
broad as the front edge of the second vertebral plate of the disk. 
This genus and Pelochelys are so similar externally, especially in 
the dried or stuffed specimens, that the specimens were named alike 
in the British Museum, and so remained for years, though in the 
meantime they had been examined by several herpetologists, both 
English and foreign. It is only by a slight difference in the length 
of the head, compared with the width and the flatness and slight 
convexity of the forehead, that they can be distinguished, different 
as the forms of the skulls are. 
1. Currra inpica. (Skull, figs. 11, 12.) 
Testudo chitra, B. Hamilton, Icon. ined. 
Trionyx egyptiacus, var. indicus, Gray, Illust. Ind. Zool. i. t. 80. 
Trionyx indicus, Gray, Syn. Rept. 47. 
Chitra indica, Gray, Cat. Tort. B.M. 49; Cat. Shield Rept. B.M. 
70 (part), t. 41 (skull). 
Gymnopus lineatus, Dum. et Bib. Erp. Gén. ii. 491. 
