of the Animals of the Farm. 
401 
have a portion of the posterior edge untouched, as shown in the 
following illustration of the mouth of a two-jear-old fillj. 
Fig. 9. — Incisors of Cart-filhj at two years. 
Between two and three years of age the central temporary 
incisors of the horse are changed for permanent teeth, and the 
different phases of the change are sufficiently well defined to 
assist the examiner in deciding whether the animal is two years 
off or coming three years. 
At two years off, or two years and a quarter, there will be 
evident signs of the shedding of the upper central incisors. The 
gum at the necks of the teeth is somewhat sunken, and the 
colour is rather deeper than in other parts. Very soon a red 
line appears in this position, and it is evident that one or both 
of the temporary teeth are only held in their places by a small 
portion of the fang which has not yet been absorbed. At two 
years and a half the permanent teeth will generally be in the 
mouth. Perhaps one temporary central incisor may yet remain ; 
but even in that case the state of the permanent teeth will be 
sufficient evidence of the animal's age. 
VOL. XVIII. — S. S. 2d 
