The Digestive System. 37 



The wearing surface (upper) is known as the table of the 

 tooth, and it is on the tables of the front teeth (incisors) 

 that the various marks are seen which are treated of when 

 discussing the age of a horse. As to kinds of teeth there 

 are two, classifying them according to their construc- 

 tion, viz.: Simple, e. g., the nippers or incisors, and the 

 tusks or tushes (canines) ; CoHipow?uZ, the grinders (molars). 

 The teeth will be considered according to their location, 

 hence three sets those at the front, nippers or incisors, 

 the tushes or canines, and the back teeth, known as the 

 grinders or molars. 



The incisor teeth in horses, cattle and sheep are made 

 use of by the stockman to determine the age of the ani- 

 mal, by taking into consideration the time of appearance 

 of those teeth, the amount of wear shown on their tables, 

 and by their shape. 



On the tables of the incisors the enamel forms a depres- 

 sion known as the cup or cusp, which is filled with the 

 tooth cement, generally discolored by the food, thus ac- 

 counting for the black mark found in the cup. When an 

 incisor has been in use for some time its table (wearing 

 surface) presents two irregular rings of enamel, an outer 

 arid an inner one. The inner ring surrounds the cup 

 (cusp); the dental star (so-called) is a spot on the tables 

 found at certain periods between the cup and the front 

 edge of the tooth. The tusks or canines are not always 

 present, rarely in the mare, in fact these teeth are con- 

 sidered as a mark of masculinity. In cattle and sheep 

 there are no upper incisors, as has been mentioned; the 

 incisor teeth in cattle especially are quite loose in their 

 sockets. 



