42 



ANIMAL MANAGEMENT. 



Appear- 

 ance of 

 fang-hole. 



longer periods, the variation being due to the depth of the mark and the 

 thickness of its enamel lining. 



The fcm^^-hole vi\7\kes its appearance on the wearing surface of the 

 central teeth at about eight years, as a transverse line, in front of the mark. 



Fig. II.— Six years. 



With increasing age it becomes a "spot" rather than a line, and as the 



mark disappears it occupies the centre of the table. 

 Changes of The shape of the wearhig surface becomes changed from the broad 

 shape ol ^^^ ^^ triangular, the back of the tooth forming the apex of the triangle, 

 wearing 

 surface. 



