32 
INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
true molars of these two species resemble one another ; and it appears to be very 
questionable whether, if we had only the teeth to deal with, there would he sufficient 
grounds for specific distinction. 1 This is, however, abundantly afforded by the 
difference in the form of the skulls. 
Germ of upper true molar . — In figure 5 of plate Y, there is figured a germ speci- 
men of a first or second upper true molar, presenting all the characters of the teeth 
of B. sivalensis. This specimen was obtained by Mr. Theobald from the Siwaliks 
of the Punjab, and is quite uninjured. The base of the tooth has not yet attained 
its full size, but the summits of the ridges are of the same length as in the fully 
formed teeth of the species. The * crochet ’ bifurcates at its extremity, and on 
the external or £ dorsal ’ surface of the crown there are seen to be two faint median 
ridges, which seem to disappear in the adult teeth. 
Balcer and Durand's specimen. — In figure 8 of plate IY of the first volume 
of this work, a molar of a Siwalik rhinoceros, copied from one of the plates of 
the above-quoted memoir of Messrs. Baker and ’Durand, was figured under the 
name of B. sivalensis. The teeth above described seem to show that the specimen 
in question must belong to another species, possibly to B. palceindicus. 
Last upper true molar. — In figure 2 of plate IY of the first volume of this 
work, there is figured a much worn specimen of the last upper true molar of the 
present species. That specimen belongs to a cranium in the Indian Museum, agree- 
ing in all respects with the figures of the skulls of B. sivalensis given by Messrs. 
Baker and Durand, and in the “ Eauna Antiqua Sivalensis ” ; the specimen is, how- 
ever, so much worn that the main characters of the tooth are not well shown, and, 
accordingly, another and less worn specimen has been figured in the present volume 
(pi. Y, fig. 4). This specimen, which belongs to the left side, was obtained, in com- 
pany with its fellow of the opposite side, by Mr. Theobald in the Siwaliks of the 
Punjab : a portion of the summit of the crown has been broken away at its antero- 
external angle, but the specimen is otherwise uninjured ; it is in an early state of 
wear. The specimen is characterised by the prominent ‘ buttress 5 at the antero- 
external angle, by the simple ‘crochet,’ absence of c combing-plate,’ and wide 
‘median valley,’ without any trace of a tubercle at the entrance. The ‘anterior 
valley ’ forms a triangular platform on the side of the ‘ anterior collis 5 : a faint 
tubercle at the postero-internal angle of the crown indicates a rudiment of the 
* posterior valley,’ — a rudiment frequently still more marked in B. javanicus. The 
tooth agrees very closely as regards form with the corresponding molar of he latter 
species ; the following measurements showing the difference in the size of the two 
specimens : — 
It. sivalensis. 
It. javanicus. 
Length of internal surface 
2-0 
36 
„ of anterior „ . . 
1-95 
„ of external „ 
2-4 
1-9 
1 The similarity of the teeth of these two species induced me to put in a proviso in this respect as to the identifi- 
cation of the Narbada rhinoceros with the living It. indicus.—- Supra, Vol. I, Preface, p. viii. 
