ARTIODACTYLES AND PERISSODACTYLES 
like flattened nails. It can climb both rocks and trees 
(that is, various species can), and lives in burrows, which 
Ungulates generally do not. It has very strong and 
chisel-like incisor teeth in the front of each jaw, which 
are by no means unlike those so characteristic of rodents. 
The molar teeth, however, are more like those of the 
rhinoceros. The elephants form another and an equally 
distinct group. Their characters can be readily verified 
with a little trouble. The massive form and straight 
limbs, not bent at the knee or elsewhere, and the scanty 
hair distinguish them from others; but it must be 
borne in mind that the extinct mammoth was copiously 
clad with hair, and so may have been other extinct 
forms, with whose bones and teeth we are alone 
acquainted. The trunk is a third feature, of which, 
however, there are the beginnings in the tapir. The 
gait is partly plantigrade, and the bones show that the 
fingers and toes are the unreduced number of five to 
each limb. The enormous tusks, which are in reality 
an exaggeration of the large rodent incisors, mark out 
the elephants, and the fact that only one or two of the 
particularly large molar teeth come into use at one 
time in each jaw is another feature of the living but not 
of all the extinct elephants. 
The remaining Ungulates fall readily into two groups, 
the Artiodactyles and the Perissodactyles, names which 
we owe to the late Sir Richard Owen, which may be 
fairly grouped together in contrast to either and to both 
of the two groups which we have already characterized. 
In these Ungulata vera, as they have been termed, we 
have the furthest development of Ungulate characters. 
The gait is purely digitigrade, and in connexion with 
this is a lengthening of some of the bones of the feet 
and hands. It is in this section only that horns are 
developed, while the hoofs are more perfect as hoofs. 
The fingers and toes are always reduced from the 
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