FAUNA OF THE KARNUL CAVES. 
43 
Of the fossil European members of the Atelodine group occurring above the 
Pikermi horizon the one which apparently comes nearest to the Karnul rhinoceros is 
R. etruscus. The upper cheek-dentition of that species is, however, apparently 
somewhat more brachydont, while the upper premolars usually have a very distinct 
horizontal cingulum on their inner aspect, 1 and are larger in porportion to the true 
molars. The latter are, however, very like those of the fossil, and show a cingulum 
on the inner aspect of the anterior collis in the two last of the series, 2 although the 
second costa does not extend to the base of the crown. The mandible also approaches 
the Karnul jaw in general contour, but the symphysial channel is shallower and less 
defined, while the outer surface of the horizontal ramus inclines less inwardly in 
front of pm. 3, and the mentary foramen is usually double and has its hinder aperture 
placed below pm. 2 instead of pm. 3, and nearer to the inferior border of the ramus ; 3 
there is also a distinct cingulum at the two extremities of the outer surface of the 
lower cheek-teeth. 4 
Of the two existing African rhinoceroses R. simus has no affinity with the 
present form, but R. bicornis appears very closely allied. The upper cheek-teeth of 
the latter have, however, considerably higher crowns, the second costa in the true 
molars does not extend to the base of the crown, and the buttress in the same teeth 
appears less strongly marked, while the premolars have a slight cingulum, which 
does not present an oblique ridge on the posterior collis. The contour of the in- 
ferior border of the mandible is also more curved, 5 but the hinder part of the 
symphysis is extremely like that of the fossil, many specimens showing the same 
well-defined channel. In most examples of the. existing species the mentary foramen 
occupies the same position as in the fossil, 6 but the symphysis of the latter was 
almost certainly somewhat longer anteriorly, and was perhaps intermediate in this 
respect between R. bicornis and R. etruscus. The bicorn R. pacliygnathus of Pikermi 
appears closely allied to R. bicornis , and differs from the fossil in much the same 
respects as the latter. 
Summary — The usual ill fortune of the palaeontologist obtains in the present 
instance, for had but the mandibular symphysis of the Karnul rhinoceros been complete 
there would have been no question whether its affinities were nearest to U. etruscus and 
R. deccanen&is, or to R. bicornis. There is, however, apparently but little doubt as 
to its specific distinctness from the first of these three species ; and if it be assumed 
that the presence of the cingulum in the upper premolars, the absence of a large 
amount of cement in the cheek-teeth, the contour of the mandible, and the position 
of the mentary foramen, are constant characters in the second species, it will bo 
evident that the present form cannot be identified with the Deccan rhinoceros. The 
apparently more hypsodont dentition of R. bicornis and the difference in the contour 
1 Compare Boyd -Dawkins “ Quart. Joum. Geol. Soc.” vol. XXIV. pi. VII. fig. 1 (1868). 
2 Ibid. pi. VII. fig. 1. and VIII. fig. 4. 3 Compare “Falconer’s Palaeontological Memoirs,” vol. II. pi. XXVII. 
4 Compare Dawkins, op. cit. pi. VII. fig. 3. 5 Compare Blainville’s “ Osteographie ” — genus Hhinocei-os, pi. III. 
6 It is occasionally situated below pm. 2 - 
K 
