208—54 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
callosity is at least occasionally present), and differs in the form of the vertebral 
scutes and the nature of the sculpture, it is evidently distinct from that speciesd 
Compared witli Ghitra indica^ the fossil agrees so closely in every respect — especially 
in its great size, in the coarse sculpture of the carapace, the small dimensions of the 
5th, and the elongation of the four preceding vertebral scutes — that there can be no 
reasonable doubt of its specific identity. The following are the dimensions of the 
fossil specimens : — 
Transverse diameter of nuchal scute 11-0 
Ant. -post. ,, ,, 1st vertebral scute 3-2 
Transverse ,, ,, 2nd costal ,, 9-3 
Ant. -post. ,, ,, 3-65 
Transverse ,, ,, 5th ,, lO'S 
Ant. -post. 3-8 
The writer has not had the opportunity of comparing a full-grown existing 
specimen with the fossil, but according to Mr. Theobald the shell of the former 
attains a length of more than three feet. 
The Indian Museum possesses three fragments of costal scutes (Nos. E 112, 116, 
118) from the Siwaliks of the Punjab, which agree in respect of size and the 
structure of the sculpture with the British Museum specimens, and may accordingly 
be referred to the same species. The antero-posterior diameter of the portion 
belonging to a 2nd costal (No. E 116) is 3‘5 inches. 
Bypoplastron . — An adult hypoplastral scute from the Siwalik Hills in the British 
Museum (No. 39829) probably belongs to the present species. 
Distribution . — According to Mr. Theobald’’ the species at the present day inhabits 
“ the Ganges, Bengal, the Irawadi, and the estuaries of the Indian and Malayan 
coasts it has also been stated to occur in the Phillipine Islands.^ The fossil scutes 
in the Indian Museum indicate that its range formerly embraced the basin drained 
by the Indus. 
1 In P. cantori the first four vertebrals are relatively wider— especially anteriorly— and the sculpture is much finer. In 
Trionyx gangcticus and the allied forms the 5th vertebral is relatively larger, and the sculpture less coarse. 
2 The specimen compared was an immature one belonging- to the Indian Museum, Calcutta (No. 1779). 
3 “ Catalogue of Reptiles of British India.” p. 27. i Vide G-unther, “ Reptiles of British India,” p. 50. 
