VERTEBRATA: MAMMALIA. 71 1 



the Tragulida, and in some of the Deer. Most of the Deer 

 conform in their dentition to the above formula, but a few 

 forms (e.g., the Muntjak) have canine teeth in the upper jaw. 

 These upper canines, however, are mostly confined to the 

 males ; and if they occur in the females, they are of a small 

 size. The dentition of the Camelidce (Camels and Llamas) is 

 still more aberrant, there being two canine-like upper incisors 

 and upper canines as well. The lower canines also are more 

 pointed and stand more erect than the lower incisors, and 

 slightly separated from them, so that they are easily recog- 

 nisable. The group of the Ruminantia includes the families 

 of the Camelidce (Camels and Llamas), the Tragulidce (Chevro- 

 tains), the Cervidce (Deer), the Camelopardalidce (Giraffe), and 

 the Cavicornia (Oxen, Sheep, Goats, Antelopes). 



a. Camelidce (Tylopoda). The Camels and Llamas constitute 

 in many respects an aberrant group of the Ruminantia^ espe- 

 cially as regards their dentition and the conformation of the 

 feet. The upper jaw (fig. 407) carries three teeth on each 



Fig. 407. Side-view of skull of Camelns Bactrianus : i Upper incisor; c c Canines ; 

 j>m Isolated praemolar. (After Giebel.) 



side in front, separated by slight intervals. The most anterior 

 of these is a conical incisor; the central one is a canine, and 

 the hindmost is the first prasmolar, which is separated by a 

 wide gap from the rest of the molar series, and is pointed in 

 foim. In the lower jaw there is also a canine, placed a little 

 beaind the incisors, and a detached laniariform praemolar (the 

 latter sometimes absent). In the Llamas these isolated prae- 

 moars do not exist. Each foot terminates in two toes, which 

 are provided with imperfect nail-like hoofs, covering no more 

 thai, the upper surface of each toe. The two hinder toes, which 

 are mostly present in the Ruminants, are here altogether want- 

 ing, and the animal walks upon the hinder surfaces of the toes, 



