of the Animals of the Farm. 
405 
tlieir suiiaccs, and are not nearly level with the other teeth. 
One or two of the most projecting^ points of the sixth molars 
show the effects of attrition ; but these teeth at the age of three 
vears and a half have their posterior points close to the angle 
of the jaw and still covered with the gum. 
At four years old the horse has the lateral permanent 
incisors in apposition, and the fourth and sixth molars are level, 
or nearly level, with the other teeth. 
The tusks of the horse are often through the gums at four 
vcars of age, but they are not usually fully developed before five 
years, and occasionally they are not well up before five years and 
a half. As a means of judging the age, these teeth are of little 
importance. 
The following drawing (Fig. 13) represents the state of the 
incisor teeth on the completion of the fourth year. 
Fig. 13. — Incisors of Horse at four years. 
