464 
UNGULATES. 
Form. 
side of both the upper and lower jaw there are seven cheek-teeth; but the last molar 
in the upper jaw differs from the rest in having its hinder ridge more or less 
aborted, so that the form of the crown is generally triangular. 
As regards their front teeth, the 
different species of rhinoceros present 
a considerable amount of variation, 
some of them having such teeth in 
both jaws, while in others they are 
totally absent; but there are never 
any canine teeth or tusks in the upper 
jaw, and the number of upper incisor 
teeth never exceeds two pairs. In 
the lower jaw there may be a pair 
of large pointed and nearly horizontal 
tusks, and between them a small pair 
of incisor teeth. 
All the living rhin¬ 
oceroses are animals of 
large size and heavy build, with the 
legs comparatively short and stout, 
although less so than in the hippo¬ 
potamus. Each of the toes is furnished 
with a relatively small, but broad and 
well-defined lioof-like nail. The head 
is large and elongated, with a concave 
profile, and the erect oval ears placed 
very far back. The eyes are very 
small in proportion to the size of the 
head; and the upper lip is generally, 
although not invariably, prehensile, 
and prolonged beyond the extremity 
of the lower one. The thick skin is 
either naked, or but sparsely clad with 
hair, and may be thrown in certain 
parts of the body into a series of deep 
folds. The tail is thin and of moderate 
length. 
The horns, which 
form the characteristic 
feature of the physiognomy of the 
living species, are composed of a 
closely-packed mass of horny fibres, 
connection with the bones of the 
the latter beneath each horn. The 
Horns. 
LEFT UPPER MOLAR TEETH OF TWO EXTINCT SPECIES 
OF RHINOCEROS. 
Both considerably worn by use. 
growing from the skin, and having no 
skull, although there are prominences on 
skull, as shown in the figure of that of an extinct species given in the sequel, 
is characterised by its elevated occipital region, long curved profile, the absence of 
