48 THE AGE OF THE HORSE. 



of the permanent ones. These remarks, of course, 

 only apply to the incisor teeth. The cutting 

 surface of an incisor tooth is called the table, and 

 it is the alteration in the shape of the latter, 

 through wear, that enables one to form an 

 opinion, as to the age. The outer boundary of 

 the table is circumscribed by an enamel ring. 

 This is called the " outer " enamel ring, in order 

 to distinguish it from a smaller enamel ring 

 occupying the centre of the table, and termed the 

 " inner " enamel ring. This ring surrounds a central 

 mark, or cavity, known as the infundihulum, but 

 to horsemen simply as the " mark." In a tooth 

 recently cut this mark extends right across the 

 table ; but, as wear advances, it alters in its shape, 

 ultimately becoming completely obliterated ; but 

 this does not take place till the animal is ten or 

 twelve years old, being then spoken of as " aged." 

 The number of temporary incisor teeth is twelve, 

 six in the upper, and six in the lower jaw. There 

 are also twelve temporary molar teeth, three on each 

 side of the upper and lower jaws, and for the con- 

 venience of study it is usual to speak of these in each 

 jaw as the first, second, and third temporary molars, 

 in contradistinction to those which subsequently 

 follow, and called the fourth, fifth, and sixth per- 



