TEN YEARS 

 UPPER INCISORS 



ELEVEN YEARS 

 UPPER INCISORS 



FIFTEEN YE.ARS 

 LOWER INCISORS 



Passing to the permanent incisors in the upper jaw at nine years the 

 central pair have almost completely lost their mark. At ten those 

 adjoining these have reached the same condition, while at eleven the 

 marks have about vanished from all of the permanent incisors. It 

 will be noticed that as the age advances the appearance of the worn 

 tables assumes a more triangular form. 



TWENTY ONE YEARS 

 FIVE YEARS 



Comparison of a five-year-old mouth with one that is twenty years 

 old, showing the marked contrast that develops, as age advances, in 

 the slope of the teeth as viewed from the side. To Goubaux and 

 Barrier's "Exterior of the Horse" the author is greatly indebted for 

 the prints of horses' teeth which have been shown. These have been 

 modified somewhat to bring out more clearly the necessary distinctions. 



