8 
MOLAE TEETH AND OTHER REMAINS OE MAMMALIA. 
would be soon obliterated. The whole inner border of the tooth forms a nearly 
straight line; the dorsum has a single vertical groove; there is no cingulum on any 
part of the crown ; the enamel has a nearly uniform thickness. The length of the 
specimen is 2'2 inches and its greatest breadth I'l inches. 
This tooth differs from Falconer’s figure by the inner wall of the median collis 
being longer and flatter, and by the obliquity of the median enamel wall to the long 
axis of the crown. The tooth is, however, nearer to those of this species than to 
those of any other. 
The mandible of this species is spatulate and provided with one large broad 
incisor on each side. 
Rhinocehos sivalensis, Falconer. Plate 4, figs. 2 & 8 ; and Plate 5, figs. 2 & 5. 
Of this species I have figured a very splendid specimen of the upper second 
molar of the left side, collected by Mr. Theobald in the Siwaliks of the Pot war 
district. Figures of penultimate and ultimate molars of the right maxilla are 
given in Messrs. Durand and Baker’s paper, noticed above ; these figures have been 
copied in De Blainville’s “ Osteographie ” {Vol. IIT^ plate 4). I have again 
copied the figure of the penultimate molar, as it presents slight differences from our 
specimen. I have also figured {plate 4, Jig. 2) the ultimate molar of the right 
side taken from a cranium in the Indian Museum, collected by Mr. Theobald ; this 
tooth, though considerably worn down, still shows the general relations of its com- 
ponent parts. 
Taking first the specimen from the Potwar {Jig. 5 ), we find the general shape 
of the crown is approximately square, with a protrusion at the antero-externajl angle. 
The anterior collis ( left side of Jigure ) is considerably the larger of the two ; it is 
a blunt cone in form ; the worn dentine surface of this collis runs obliquely towards 
the antero-external angle of the crown ; there is a vertical hollow on the anterior 
surface of the collis. The median valley ( centre of figure ) runs in approximately 
the same direction as the dentine surface of the anterior collis ; it becomes deeper 
as it passes, outwards and terminates in a triangular-shaped cavity, which extends deep 
down into the crown. The median valley is entered by an exceedingly narrow pass, 
with a sudden fall on either side ; there is no tubercle at the entrance to this 
valley, the bottom of which forms a mere line between the colies. A single pointed 
crochet extends three-fourths across the valley from the median collis. There is 
no combing-plate or antecrochet in the median valley. 
The median collis ( right side of figure ) forms a slender cone slightly twisted 
on itself ; a small but distinct third or posterior collis is seen on the right side of the 
former separated by a shallow cleft ; this posterior collis is continued outwards, 
as a narrow wall, becoming lower as it passes outwards, which forms the boundary 
to the posterior valley ( middle of right side of figure ) ; this valley is ovate at the 
top, becoming circular at the base. 
( 26 ) 
