RHINO CEROSES. 
485 
rhinoceroses without front teeth, inhabiting England and other parts of Europe, 
which had upper molar teeth of the general type of those of the common African 
species, although their skulls were very different. Of these, the Leptorhine 
rhinoceros (R. leptorhinus ) and the Megarhine rhinoceros ( R. megarhinus ) are 
found in the brick-earths of the Thames valley and other superficial deposits; 
while the Etruscan rhinoceros ( R. etruscus ) occurs in the somewhat older “ forest- 
bed ” of the Norfolk coast, and likewise in the upper Pliocene beds of Italy and 
France. The Leptorhine and Megarhine species have tall-crowned cheek-teeth, 
and (as shown in the accompanying figure) are characterised by the presence of a 
vertical bony partition in the skull dividing the two chambers of the cavity of 
the nose. In this respect they resemble the woolly rhinoceros; a rudiment of the 
same feature also occurring in the living Javan rhinoceros. The Etruscan 
rhinoceros, on the other hand, has shorter-crowned cheek-teeth, and no such bony 
septum in the nasal cavity. That all these three species browsed on leaves and 
twigs may be pretty confidently asserted from the structure of their upper molar 
teeth; while a carcase found embedded in the ice of Siberia belonging to either the 
Leptorhine or the Megarhine species, shows that these had smooth skins like the 
living rhinoceroses of Africa. The Deccan rhinoceros ( R. deccanensis ) and the 
Karnul rhinoceros ( R. karnuliensis), from the superficial deposits of Southern 
India, indicate that smaller representatives of the two-horned branch-eating group 
likewise inhabited that country. 
Reference has already been made to the occurrence in the Miocene deposits of 
Europe of an extinct two-horned rhinoceros provided with upper and lower front 
teeth, which was allied to the living Sumatran species. Throughout the middle 
Tertiary rocks of Europe, as well as in the Pliocene and Miocene of India, there 
are found, however, a number of rhinoceroses differing from any living species in 
the total absence of horns, while in those cases where their limbs are known the 
fore-feet were provided with four toes. Some of these animals were of very large 
size, and all of them had molar teeth of the type of that represented in the upper 
figure on p. 464 (which belongs to one of the Indian species), and their jaws were 
furnished with large front teeth. Moreover, in one of the Indian representatives 
of this hornless group, the last molar tooth was of nearly the same form as that 
in front of it, instead of being triangular. That all these species subsisted on 
leaves and boughs, may be inferred from the structure of their short-crowned 
molar teeth; and it may be observed here that all the older Ungulates had short- 
crowned cheek-teeth, adopted for champing twigs and leaves rather than for 
masticating grass; whence it may be concluded that grassy plains are probably a 
comparatively recent feature in the history of our globe. Hornless rhinoceroses 
also occur in the Tertiary deposits of North America, but at least the majority of 
these resembled existing types in having but three toes on each fore-foot; while 
their limbs were relatively shorter than in their Old World allies, and their bodies 
more elongated. Finally, there were certain other small rhinoceroses from the 
lower Miocene of both Europe and the United States, in which the front of the 
skull carried a very small pair of horns placed transversely instead of longi¬ 
tudinally. 
The above are all the forms which can be included in the genus Rhinoceros. 
