EOCENE CHELONIANS EROM THE SALT-RANGE. 
65 
while the absence of a nuchal shield affiliates it with the existing Sternothcerus, 
Pelomedusa, Podocnemis, and Peltocephalus. From the first (woodcut, p. 61) it is 
readily distinguished by the much longer vertebral hones. By the unfortunate 
absence of the pygal region and the greater part of the plastron, the best distinctive 
characters of several of these genera are not available. Podocnemis is, however, 
distinguished from the others by the great length of the band uniting the plastron 
with the carapace, and its thick shell ; in both of which respects the fossil agrees 
with it. Podocnemis contains, moreover, the largest living member of the family ; 
and both the young of P. expansa and the adult of P. dumeriliana are characterised 
by their tectiform carapace; in which respect they also agree with the fossil. 
The close resemblance in the general contour of the fossil carapace and that of the 
latter species has been already alluded to, and since I can find no points of generic 
distinction between the former and the existing species of Podocnemis, I think 
the fossil may be at least provisionally referred to that genus 1 with the name of 
P. indica. 
Podocnemis, it need scarcely be observed, is at the present day confined to 
South America ; but its occurrence, together with that of Platemys, in the lower 
eocene of Western India, and also in the corresponding formation of England, 
indicates that the original home of this group of fresh-water Chelonians was in the 
northern hemisphere of the Old World, from which they have been driven in all 
probability by the competition of the Bmydidce to find a home in the southern half 
of America. 
1 1 have not been able to compare the fossil with a recent Podornemis in which the horny shields have been stripped 
from the carapace. 
