DE.XTAL INDICATIONS OF THE AGE OF A HORSE. 229 



socket, are at first oval and then rounded, and of a 

 triangular form towards the base of the root, with the 

 extremity flattened from side to side. This variation is 

 much more remarkable in the nippers and dividers than in 

 the corner teeth, which is rendered more obvious by making 

 several sections of an incisor tooth at somewhat about a 

 quarter of an inch apart. We have given five transverse 

 sections of the tooth of a young horse to exhibit this : plate 

 V. figs. 13, 14, 15, 16, and 17, have the funnel, and the 

 sections, 16 and 17, show the septum of the root of the 

 tooth. 



The incisors of the upper jaw are stronger, broader, 

 and more developed than those of the lower ; consequently 

 the outer edge of the lower corner teeth rest against tlie 

 centre of the upper corners, and wears them in such a 

 manner as to produce in some jaws a triangular nick, which 

 leads in a certain degree to the determination of the age of 

 a horse. This nick never appears until the horse has 

 attained its seventh year. It becomes obliterated in time, 

 but sooner in proportion as the jaw assumes a horizontal 

 direction. 



We have given representations of six teetli, showing the 

 exterior of the incisor teeth, together wdth their internal 

 organization. 



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 ; h, 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. 1 0, a. 



The molars, or grinding teeth of Old Billy, mentioned at 



