DENTAL INDICATIONS OF AGE OF A HORSE 199 



ing the exterior of the incisor teeth, together with 

 their internal organisation. 



The tooth of a foal viewed from its posterior or 

 inner surface. Plate v, fig. 8, a, the mouth of the 

 cavity of funnel of the table. 



Another foal's tooth, viewed anteriorly, fig. 7 : a, 

 exhibits the body of the tooth ; b, the neck ; and c, 

 the root. 



The tooth of a very young foal, in which the 

 casing or outer enamel is cut through its whole 

 length, and exhibiting the central enamel, fig. 10, a. 



The molars, or grinding teeth of "Old Billy," 

 mentioned at page 197, are worn in a singular 

 manner. The first grinder of the lower jaw, on 

 both sides, is worn down to about half-an-inch above 

 the gum ; the second, on a level with the gums, form- 

 ing a hiatus into which the second grinder of the 

 upper jaw fits, which is fully a quarter of an inch 

 longer than the first grinder, and very uneven and 

 unequal on the surface. About half-an-inch of the 

 outer portion of the fourth grinder is parallel with 

 the third, but the remainder is worn level with the 

 jaw ; the fifth and sixth molars are almost entirely 

 worn down, except a small portion of the inner part 

 of the sixth. The third upper one is more than 

 half worn down, and the fourth level with the socket ; 

 part of the fifth and sixth are worn obliquely down, 

 the cavity formed by which is occupied by the lower 

 opposite teeth, and the worn down fifth and sixth 

 of the lower jaw are occupied by the upper ones. In 

 short, it is curious how mastication could be per- 

 formed. 



It seems probable that the natural age of the 

 horse is from thirty-five to forty. It would be most 

 erroneous to estimate his life according to the age 



