20 
MOLAK TEETH AND OTHER REMAINS OE MAMMALIA. 
The characteristics of the upper molars of this species may he shortly sum- 
marised as follows : — 
‘^Buttress at antero -external angle; anterior eollis tlie larger; crochet simple and blunt; 
median valley very wide; broad tubercle at entrance; blunt antecrocbet and anterior eollis. No 
combing-plate, and only two fossettes on the worn- crown.” 
The only one of Ealconer^s three species of Siwalik ’Rhinoceros to which the 
molars of the present species have any resemblance in form is Rhinoceros siva- 
lensis ; the teeth of both these species agree in having a buttress at the antero- 
external angle, in the anterior eollis being larger than the median, in the absence 
of a combing-plate, and in the presence of two fossettes only on the worn-crown. 
They are distinguished by the following points : — 
In jR. simlensis there is no antecrochet ; neither is there any tubercle at the 
entrance to the median valley, nor any trace of a cingulum on the inner surface. 
The median valley is very wide in R. iravadicus, and very narrow in R. simlensis. 
The cingulum on the anterior surface of the latter is cleft, and forms a wall above 
a distinct anterior valley ; in the former this cingulum is not cleft, and merely 
forms a flat ledge, without any distinct anterior valley : the process at the postero- 
external angle is much more produced in R. simlensis than in R. iravadicus. 
Erom the molars of R. palceindicus the present specimens are distinguished by 
the presence of only two fossettes on the worn-crown ; and from those of R. platy- 
rhinus and R. namadiciis by the absence of the combing-plate and by the presence 
of two fossettes only on the crown. 
There is no marked resemblance between the molars of any of the European 
species and these specimens i from the molars of R. tichorJiinus, R. leptorhinus, 
Cuv., R. hemitcecus, Ealc., and R. Indicus, the present specimens are distinguished 
by the absence of any combing-plate. 
The presence of the large tubercle in the median valley distinguishes the teeth 
of R. iravad'icus from those of R. etriiscus, Ealc., and R. deccanensis, Eoote. 
Erom R, sinensis of Owen they are distinguished by most of the above charac- 
ters, and by the fact of the median valley becoming deeper as it passes outwards, 
instead of becoming shallower. 
They approach nearest in form to the molars of the recent Rhinocerus stma- 
irensis and R. javaniciis; all the species having the buttress at the antero-external 
angle and the wide median valley, with occasionally a small tubercle at the en- 
trance ; they are, however, distinguished by the nearly horizontal line formed by 
the free boundary of the dorsum, in place of the angulated line of the recent 
species ; the two colles are more equally sized in the recent species, the ante- 
rior valley smaller, and the cingulum less marked : the crochet is larger and extends 
further across the valley in the recent species ; and from the larger diameter of the 
median eollis, the posterior valley is smaller. It is, however, quite probable that 
the Rhinoceros of the Irawadi may have been the direct ancestor of the recent 
( 38 ) 
