SI W ALIK KHINOCEROTUm 
45 
The dimensions of our specimen are as follows : — 
Length of last premolar 1'4 
Width of „ T9 
Length of first true molar 1‘5 
Width of „ „ 2'05 
Length of second „ .1/9 
Width of „ (P)2-4 
These measurements show that there is a very considerable difference in the 
size of the two specimens ; the dimensions of the second upper true molar of Fal- 
coner’s specimen being 2*4 X 3 - 2 inches. The general resemblance between the teeth 
of the two specimens is, however, so close that ' I do not consider there is any evi- 
dence at present to warrant us in separating the two. We have already seen that the 
molars of Falconer’s specimen seem to be slightly different from those of what may 
be called the type specimen, and in the Punjab specimen we have this slight differ- 
ence in form accompanied by a difference in size. If all three specimens belong, as 
appears probably the case, to one species, we have another excellent instance of the 
variation to which a species may be subject. 
British Museum shull of small race.— In the British Museum there is an im- 
perfect cranium of a Siwalik rhinoceros, not figured in the “ Fauna Antiqua Siva- 
lensis,” but labelled R. palceindieus, of which a cast is now in the Indian Museum. 
This cast shows that the cranium is imperfect superiorly, but the portion of the 
frontals remaining shows the great breadth characteristic of the skulls of R. palcein- 
dicus. The specimen exhibits the greater portion of the molar series of either side, 
but unfortunately every tooth has been split vertically and lost more or less of its 
outer half. The inner halves of the first and second true molars and the greater 
part of the two last premolars are fairly well exhibited. The true molars of this 
specimen, as far as can be judged from what remains of them, agree in general 
form with those last described, but are of slightly larger dimensions, thus breaking 
down the gap between the latter and Falconer’s specimens. The premolars of this 
specimen, however, present a divergence in another direction. In place of having 
merely a small ledge at the entrance to the 5 median valley,’ as in the Punjab speci- 
men, the last premolar has a distinct ‘ cingulum ’ along the whole of the inner side, 
and makes some approach to a tooth from Sind, represented in plate VI, figure 6 of 
the first volume of this work as a premolar of Acerotlierium perimense. Taking 
into account, however, the resemblance of the skull in the British Museum to the 
skull of R. palceindieus , and of its true molars to those of the Punjab specimen, 
which we were unable to separate from that species, I cannot think the materials at 
present available would justify us in assigning the British Museum skull to a distinct 
species merely on account of the variation of one premolar. If this reference be 
correct, it shows how very uncertain must be any evidence, founded on a single 
premolar tooth, as to the species of its owner. 
Last upper premolar. — In figure 2 of plate VII of this volume, there is repre- 
sented one of two similar upper premolar teeth of a rhinoceros, obtained by Mr. 
