52 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
of the nasal 4 cloison, 5 of which there is no trace in the Indian fossil. The true 
molars of the two forms, though presenting great general resemblances, as far as 
I can judge, are distinguished by the fact that in the Indian species the entrance 
to the c median valley 9 is open nearly to its base, whereas in the European it is 
blocked by a c pass, 9 joining the bases of the two c colies 9 , sometimes for a distance 
of nearly half their height. 
The living African rhinoceroses are distinguished by the abortion of the pre- 
maxillae, from the present species, in which they are well developed. In the true 
molars of R. bicornis an 4 accessory fossette 9 is not normally present. In R. simus 
the peculiar blunted form of the nasals is a very distinguishing character. Erom 
R. pachygnathus of the European miocene, the present species is distinguished by 
the characters of the upper molars, those of the former not presenting an 4 accessory 
fossette 9 d the upper molars of the Indian JR. deccanensis of the pleistocene, 
probably also a bicorn form, present no close resemblance to those of the present 
species. 
Upper milk-molars. — In figure 4 of plate YII there are represented two small 
upper molars of a rhinoceros from the left side of the jaw. The figure is taken 
from the cast of two teeth in the British Museum, where they are, I believe, 
labelled as milk-molars of JR. palceindicus : they were obtained from the Siwaliks. 
Erom the small size of these teeth, together with their general form, there can be 
no doubt but that they belong to the milk-molar series ; while from the considera- 
tions advanced in treating of the milk-molars assigned above to R. sivalensis, they 
must be respectively the second and third of that series. 
The anterior tooth (mm. 2) is of somewhat irregular form, as is generally the 
case with the early milk-molars, and carries a bold 4 costa 9 opposite the entrance to 
the ‘median valley. 9 The hinder tooth (mm. 3) is of the regular form, and carries 
a distinct 4 costa 9 opposite each of the 4 colles ’, the anterior being the most developed. 
Both teeth exhibit clearly the presence of a large ‘crochet 9 and a 4 combing-plate, 
which unite to form an ‘accessory fossette. 9 There are also rudiments of additional 
4 combing-plates.’ A 4 cingulum 9 is present on the anterior surface of each tooth. 
The entrance to the 4 median valley ’ is perfectly free and open, without any trace 
of a ‘pass. 9 
The large size of the 4 combing-plate 9 and its distinct union with the 4 crochet 9 
to cut off a very large 4 accessory fossette 9 , in both these teeth, sufficiently distin- 
guishes them from the milk-molars referred above, respectively, to R. sivalensis 
(pi. VI, fig. 2), R. palceindicus (pi. YII., fig. 3), and Acerotherium perimense (pi. Ill, 
fig. 2). There is, therefore, every presumption that they should be referred to 
R. platyrhinus , a presumption rendered almost a certainty by the agreement in the 
general characters of these teeth with those of the true molars of that species. 
This provisional reference has a bearing on a tooth described and figured in the 
previous volume of this series (pi. YI, fig. 10). In describing that specimen 
1 See “ Animaux Fossiles et Geologie de l’Attique,” plate XXVII, fig 2. 
