UNGULATES. 
158 
THE FIRST MOLAR AND THE THREE 
PREMOLAR TEETH OF THE RIGHT 
SIDE OF THE UPPER JAW OF THE 
FOUR-HORNED ANTELOPE. 
than the premolars. This is shown in the accompanying figure, where the first of 
the three upper molar teeth is shown on the left side, and is seen to consist of two 
lobes, while the adjacent premolar has but a single lobe. Another feature connected 
with the teeth is exhibited by the last molar in the 
lower jaw, which almost invariably consists of three 
lobes; whereas in the living representative of the 
odd-toed Ungulates it has only two lobes. In their 
single - lobed upper premolar teeth the even-toed 
Ungulates show a retention of the primitive triangular 
type of tooth, which has been lost in the molar teeth. 
Then again the thigh-bone, or femur, in all the 
members of the present group is characterised by the absence of any projecting 
process on the hinder surface of the shaft. 
There are other less obvious distinctive features of the even-toed Ungulates, 
but the above are sufficient for our present purpose. It must be added, however, 
that both in this group and in the odd-toed Ungulates there are never more than 
four toes to each foot; and that all the members of both groups walk on their toes 
alone. 
We are now in a position to consider somewhat more closely the 
characters of the hollow - horned Ruminants, but we have still to 
notice that these, together with the giraffe, the prongbuck, and the deer, form a 
Ruminants. 
SKELETON OF THE EUROPEAN BISON. 
group distinguished from all the other even-toed Ungulates by certain important 
characters. In all the members of this assemblage of four families there are no 
front (or incisor) teeth in the upper jaw; and the upper tusks or canines are 
