168—14 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
If the two specimens noticed above be specifically the same, and Mr. Theobald 
be right in regarding the second one as indicating an animal witli aquatic habits, it 
may be that the present species was a tortoise allied to Colossochelys atlas and Manouria 
emys^ having the subaquatic habits of the latter species still more strongly developed, 
and thus pointing to the origin of the whole group from an earlier purely aquatic form. 
I ‘ 
Species 3. 
(About one-fourth larger than T. elepJiantina.) 
Epiplastron. — The evidence of the existence of a fourth species of gigantic 
land-tortoise in the Siwaliks is afforded by the anterior portion of an epiplastron 
represented of one-third the natural size in pi. XVIII. fig. 2, which was collected by 
Mr. Theobald in the Siwaliks of the Punjab. The specimen, of which the dorsal 
aspect is represented in the figure, is in a much damaged condition, and does not 
exhibit the boundaries of the horny plates : it indicates an animal perhaps slightly 
larger than the preceding species. In general contour it presents a considerable 
resemblance to the epiplastron of the latter, but is distinguished by its relative 
shortness, and much greater thickness ; the length of the dorsal thickened portion to 
the extremity of the bifurcation being 5 '6, and the vertical thickness posteriorly 
something over 5 inches when complete. The anterior cornua are thicker, more 
upwardly recurved, and more widely separated than in the last form. 
Distinctness and affinities . — The differences between the present specimen and the 
epiplastron of the last form are so marked as apparently to preclude the idea that 
they can belong to different sexes of the same species ] and the observations recorded 
as to the specific distinctness of the latter will be equally applicable to the present 
form. The imperfect nature of the specimen under consideration, and the slight 
glimpse it affords of the affinity of the tortoise to which it pertained, renders it 
undesirable that it should receive a specific name ; and it is described merely to 
illustrate the great development which the present group attained in the Siwalik 
period. 
Species 4. 
(Rather smaller than Testudo elephantina.) 
Histoip . — In 1879 Mr. Theobald’^ referred to some epiplastral and other portions 
of the shell of a species of land-tortoise obtained by himself from the Siwaliks near 
Nila in the Punjab, which indicated an animal considerably exceeding in size the 
existing Manouria eniys : these and other specimens from the same district form the 
subject of the present notice. 
Epiplastron . — Among Mr. Theobald’s collection are the detached right and left 
epiplastral scutes evidently belonging to different individuals of the same species, 
and pertaining to a land-tortoise : these specimens are combined and figured of one- 
third the natural size in pi. XIX. figs. 1. la.; and show the entire form of the gular 
1 ‘ Eec. Geol. Surv. Ind vol. XII. p. 187. 
