204 



AGE OF ANIMALS. 



FIG. C. 



" At six years the mark is almost gone from the second 

 pair, and the outer edge of the corner teeth is worn down. 



" At seven years the mark is entirely gone from the second 

 pair, and the edges of the corner teeth are worn somewhat 

 flat. 



" At eight years the teeth of the lower jaw are worn en- 

 tirely flat, the mark having disappeared from all of them. 

 The form of the surface of the tooth has become oval, and 

 the central enamel is long from side to side, and is near to 

 the front of the tooth. 



" At nine years the middle nippers are rounded on the 

 inner side, the oval of the second pair and of the corner 

 teeth becomes broader, the central enamel is nearer to the 

 inner side, and the marks have disappeared from the teeth 

 of the upper jaw. 



" At ten years the second pair are rounded on the inner 

 side, and the central enamel is very near to the inner side. 



