158—4 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
and employed in a generic sense. In a previous memoiP written before he was 
aware of the non-union of the pygals the present writer thought that the species 
might be referred to Testudo. 
Epiplastron. — The most characteristic portion of the whole shell is the anterior 
part of the plastron, of which several specimens comprising the anchylosed 
epiplastral and parts of the contiguous scutes are preserved in the British and Indian 
Museums ; all the specimens having been obtained from the Siwalik Hills. In plate 
XVIII. figs. 1, la, tliere are given dorsal and ventral views, one-sixth the natural 
size, of this portion of the epiplastron ; the figures have been made by combining 
the two most perfect specimens in the British Museum, one of which shows the free 
extremities of the epiplastron, and is figured from the ventral aspect in “ Falconer’s 
Paleontological Memoirs,” vol. I. pi. XXX. fig. 1, while the other shows their 
junction with the body of the plastron. The dorsal view (fig. 1) shows that the 
middle portion of the epiplastron, which carries the gular plates, is enormously 
thickened ; the thickened portion being continued on either side as a curved rim 
covered by the postgular plates. The production of the gular far in advance of the 
postgular portion is a character in which the fossil agrees with Manouria emys^ and 
difEers' from Testudo liorsfieldi Siwdi ihQ allied forms; but in the backward projection 
of the hinder portion of the gulars on the ventral aspect (fig. la) and the acute 
angle formed by the junction between the sutures separating the gulars and post- 
gulars it more resembles T. horsjieldi and its allies. The slight bifurcation occurring 
in the epiplastron of Manouria emys is enormously exaggerated in the fossil, the free 
extremities forming distinct cornua, while the remaining portion of the dorsal 
surface is deeply concave. On the ventral aspect (fig. la) the portion covered by 
the gulars, instead of being merely marked by the V-shaped suture bounding those 
plates as in tortoises like T. horsjieldi^ forms a very distinct triangular keel, projecting 
beneatli the portion covered by the postgulars, and expanding anteriorly into the 
cornua. The inferior aspect of the whole gular portion is strongly convex and 
distinctly impressed by the intergular suture. The extremely elongated epiplastron 
indicates that the whole plastron was long in proportion to the carapace, as in 
Manouria emys. 
None of the gigantic recent land-tortoises have an epiplastron at all approaching 
that of the fossil ; the gular portion of the epiplastron in Testudo elephantina and its 
allies® being very small and entirely in advance of the postgulars; and the intervening 
suture forming almost a straight line. No recent tortoise has the inferior keel of 
the fossil. 
In the two large British Museum specimens of the epiplastron of the Siwalik 
fossil the thickness of the gular jDortion at its contracted juction with the postgular 
is 6'5, and its width 8'0 inches ; while in the smaller Calcutta specimen (Indian 
1 ‘ Journ. As. Soc. Beng.’ vol. XLIX. pt. II. p. 16. (1880). 
2 Vide Gray, “ Catalogue of Shield-Eeptiles,” pt. I. pi. III. [M.fiisca). 
3 Gunther, “ Gigantic Land-Tortoises,” pis. IV. VI. VII. 
