140 



AGE OF THE DOMESTIC ANIMALS. 



prognathism of the lower jaw, or a deficiency of the teeth of 

 the upper jaw. It is usually limited to the pinchers and inter- 

 mediate teeth (Fig. 147). This condition is more frequent in 

 mules than in horses, and produces great inconvenience in 

 seizing food, frequently requiring operative interference. 



Fig. 148. 



Deficiency of length of incisors of the lower jaw. A, dental tables. B, roots 

 shown in their alveolar cavities. 



EXCESSIVE LENGTH OF SINGLE TEETH OF THE JAW. 



Mouths occasionally are seen in which only one, two, or a 

 small number of teeth are distorted ; this occurs at times on one 

 side only, or it occurs frequently that the teeth on one side are 

 very long and those on the opposite side very short, correspond- 

 ing with an inverse condition in the other jaw. In cases like 

 this it should always be the rule, as is necessary in all horses 

 to determine age, to inspect them from both sides. In horses of 



