58 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
With regard to R. platyrhinus, theref is some difficulty in deciding to which 
group of the genus it should he referred. 1 If the lower jaw assigned to it in 
this work really belong to it, it would appear, as said above, that the species must 
be a modified form of the Atelodus group, to which belong the living African 
rhinoceroses, the Pikermi R. pachygnathus, and, as modified forms, the four newer 
pliocene and pliestocene British bicorn species. The Indian form had not the 
aborted premaxillse of the Pikermi and African species, and is further distinguished 
from the two latter by the union of the inferior squamosal processes ; it is, therefore, 
difficult to imagine this species to have been a direct ancestor of either of the living 
African forms. In the form of its upper molars R. platyrhinus agrees very closely 
with R. simus. Similarly the upper molars of R. pachygnathus approach those of the 
African R. hicornis ; but the same difference in the relations of the inferior squamosal 
processes occurs in these species. In both instances, however, the general similarity 
of the form of the skulls would seem to indicate some kind of relationship between 
these four species as respectively coupled ; the precise nature of this relationship, 
however, cannot at present be more closely pointed out. 
The pleistocene Indian R. deccanensis, judging from the shape of its mandible, 
as already said, would also seem to be a bicorn form, belonging to a modification of 
Atelodus. Erom the shape of its mandible, the species shows resemblance to the 
British fossil forms of the group ; but the structure of its upper molars indicates 
affinity with older forms of the family. 
Nothing can be predicated as to the subsequent history of the Indian form 
known as Acerotherium perimense. 
List of the more important recent memoirs and notices hearing on the osteology and 
paleeontology of Acerotherium and Rhinoceros consulted in the writing of the 
foregoing memoir. 
Baker, W. E., and Durand, H. M. 
“ Sub-Himalayan Eossil Remains of the Dadupur Collection.” c Jour. As. Soc. Bengal , 3 
Yol. Y, p. 486. 
Blainville, De. 
“ Osteographie.” Genus Rhinoceros. Paris, 1834. 
Blythe, E. 
“ A memoir on the living Asiatic species of Rhinoceros.” £ Jour. As. Soc. Bengal , 3 
Yol. XXXI, p. 151. 
“ Letter respecting R. crossi (Gray) .” ‘ P. Z. S. ' 1861, p. 306 (shows R. crossi = R. suma- 
trensis ) . 
Brandt, J. F. 
“ Ohservationes ad Rhinocerotis tichorhini historiam spectantes.” ‘ Mem. d. Acad. Imp. 
d. Sci. d. S. Petersburg 3 7th ser., Yol. V, pi. XXIV. 
1 Professor Flower ( loc . cit., p. 457), in noticing the Siwalik species of rhinoceros, appears to have forgotten the 
existence of this form, as he talks of all the Siwalik species being unicorn, and referrible to the restricted group 
Rhinoceros. 
