MOLAR TEETH AND OTHER REMAINS OE MAMMALIA. 
11 
mandible is but little produced in front of this tooth, and seems to have been un- 
provided with incisors. 
Rhinoceeos plattehinus, Falconer. Plate 4, fig. 4. 
The subjoined description of the upper molars of this species is partly derived 
from the restored figure of a penultimate upper molar of the right side given in 
the “Eauna Antiqua Sivalensis” {plate 76, Jig. 11 a) : [this Jigu7'e is copied m the 
pv'esent paper (plate 4, Jig. 4,) on a scale of one-half the natm'al size and partly 
from a cast of the molars of the complete cranium of the species discovered by 
Colonel Baker, and now in the British Museum. The species is confined to the 
Siwaliks. 
The specimen in the accompanying figure is the above-mentioned penulti- 
mate right upper molar ; the transverse diameter of the anterior collis {on the right 
of the figure) considerably exceeds that of the median collis {on the left) ; the 
base of the median collis overlaps that of the anterior collis, so that, in the 
position of the figure, no part of the base of the median valley externally to the 
crochet is visible from the front. The anterior collis forms a thick depressed cone, 
projecting on the posterior side into the median valley. The median collis is un- 
symmetrically shaped, the posterior wall being nearly vertical, while the anterior 
boundary forms an irregular convex line, blocking the entrance to the median valley. 
The pass to this valley is sharp and well marked, somewhat external to the inner 
boundary of the tooth, and as high as the level of the cingulum, with an abrupt 
descent into the valley. There is no tubercle obstructing the entrance to the median 
valley, which winds between the bases of the two colies as a narrow sinuous line. 
The crochet is given off from the side of the median collis nearly at right 
angles to the inner border of the tooth, and has a loop of enamel on its external side ; 
in the angle formed between the internal wall of the crochet and the anterior wall 
of the median collis there is a small fold of enamel ; the base of the crochet is but 
slightly constricted ; the anterior wall of the crochet slopes towards the inner side 
of the tooth, so that the bottom of the valley is very narrow at this point ; the 
whole of the bottom of the valley, from the entrance as far as the crochet, forms, 
therefore, a mere line betw^een the colles. 
Externally to the crochet the median valley is divided into two parts by the 
combing-plate {seen at the top of the median valley), which is small and blunt, and 
forms an angle of 45° with the internal border of the tooth ; there is no ante- 
crochet given off from the anterior collis ; the anterior boundary of the median 
valley forms a line running at right angles to the inner border of the tooth, and 
there is consequently no production of the valley in the direction of the antero- 
external angle of the tooth. 
The dorsum of the tooth is marked by a slight anterior costa ; the antero- 
external angle forms a sharp edge, but is not produced into a buttress ; the postero- 
( 29 ) 
