748 



THE UNGULATES, OR HOOFED MAMMALS 



there are a few others which it is advisable to mention. One of these characteristics 

 is afforded by the cheek-teeth, in which the molars are almost always more complex 

 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 

 THE FIRST MOLAR AND THE smgle-lobed upper premolar teeth the even-toed 

 ' ?HE R^HT^ToK THE^PPER Ungulates show a retention of the primitive triangular 

 JAW OF THE FOUR-HORNED AN- type of tooth, which has been lost in the molar teeth. 

 TELOPE. Then again the thigh bone, or femur, in all the mem- 



bers of the present group is characterized by the absence of any projecting process 

 on the hinder surface of the shaft. 



SKELETON OF THE EUROPEAN BISON. 



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 

 characteristics of the hollow-horned Ruminants, but we have still to 

 notice that these, together with the giraffe, the prongbuck, and the deer, form a 

 group distinguished from all the other even-toed Ungulates by certain important 



Ruminants 



