6 
INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
Biigti teetli nmcli more closely than do those of the typical B. sivalensis. They are, 
however, at once distinguished by the greater development of the buttress and 
costae ; which stamp them as of the B. sivalensis type. The premolars of v. 
intermedins and v. gajensis are unfortunately unknown. The further consideration of 
the mutual relations of all these forms will come more conveniently in the sequel. 
The molars of Aceratherium perimense^ of which a specimen is represented in 
plate I., fig. 5 in nearly the same stage of wear as m. 2 in fig. 1 of the same plate, 
are distinguished from the Bugti teeth by the much greater development of the 
buttress and costse (c, c?), and the more marked sinuosity of the external surface of 
the crown. The ante-crochet (/) is less developed, and does not so completely block 
the median valley ; while the posterior valley (^) forms a deep funnel-shaped pit, in 
place of a slit. The tubercle {g) at the entrance of the same valley is, moreover, 
attached to both colies [a, b) ; and in some instances^ is crenulated ; while there is no 
vertical groove on the anterior face of the posterior collis {h). The premolars of A. 
perimense^ resemble the Biigti teeth in the presence of a cingulum ; but are 
distinguished by the circumstance that this cingulum, which is frequently crenulated, 
does not extend across the inner face of the posterior collis ; by the larger develop- 
ment of the second costa (c) ; and by the greater proportionate increase in the size of 
the later teeth of this series. A. perimense is also distinguished by its much larger size. 
To the molars of B. platyrliinus^ the Biigti teeth present no resemblance ; and it 
is therefore apparent that they cannot be referred to any of the previously described 
species of Siwalik rhinoceroses. Further comparisons will be instituted in the sequel. 
Mandible . — In figure 5 of plate II. there is represented a fragment of the left 
ramus of the mandible belonging to the same individual as the upper molars 
represented in fig. 4. The inner side shows the commencement of the symphysis 
immediately in advance of the socket of pm. 3. Another specimen from Gandoi 
(woodcut fig. 2) ; which from its resemblance to the last specimen, and the locality 
m. 1 pm. 4 pm. 3 
Fig. 2. Aceratherium blanfordi, Lyd. The right ramus of the mandible ; from the lower 
Siwaliks of Gandoi : Indian Museum (No. C. 271). 
from which it was obtained should almost certainly be referred to the larger race of 
the same species, shows a considerable part of the symphysis, and the alveolus of 
the right canine : while a third specimen from Gandoi {Ind. Mus., No. C. 272) shows 
the hinder part of the symphysis, and the rami of both sides : the teeth and their 
alveoli and the extremity of the symphysis are, however, wanting. A fragment of 
1 Supra., vol. II., pi. II. 2 Ibid,, pis. II.. IIa. 3 Ibid., pi. VIII. 
