288 COMPARATIVE ANATOMY OF THE TEETH. 



in the lower jaw. It is longer disappearing in those of the 

 upper jaw. 



EUMINANTIA. This order is considered to be the best 

 determined in the whole class of mammalia. 



The camel, lama, dromedary, ox, sheep, goat, stag, &c., 

 are varieties of this order. 



The genera are divided into those which are without 

 horns, and those which have them. The latter class is by 

 far the most numerous. The camel and lama are examples 

 of the former, while the ox, ram, stag, &c., are specimens' 

 of the latter. Another division is into those in which the 

 horns are solid, and those in which they are hollow. 



In the development of the horns arid teeth, the relation 

 seems to be inverse, for where the horns are present, we 

 find the canines absent, and where the horns are wanting, 

 as in the musk, canines are not only seen, but also a pair 

 of incisors in the upper jaw. 



The diiferent genera are called ruminantia, from the pe- 

 culiar faculty they possess of masticating their food a 

 second time, by returning it to the mouth after first swal- 

 lowing it. 



This singular faculty depends on the structure of the 

 stomach, or rather stomachs, which are four in number ; 

 and the first three are so related to each other that the 

 food may enter either of them, as the ossophagus ends at 

 their common point of communication. 



The first stomach is called the paunch, and receives the 

 vegetable matters from the first mastication. This passes 

 into the second, which is of honey-comb formation, and here 

 the food is moistened and compressed into little pellets 

 called cud, which is now returned into the mouth to un- 

 dergo a second mastication. It is now passed from the 

 mouth into the third stomach, which is laminated in its 

 appearance, and from this it enters into the fourth, which 

 has the rugce, and which is the seat of digestion proper. 



One characteristic in the teeth of this order is, the ab- 

 sence of incisors and canines in the upper jaw. This is 

 furnished by a callous pad as a substitute. A second char- 



