TEN YEARS 



UPPER INCISORS 



FIFTEEN YEARS 



ELEVEN YEARS LowER INCISORS 



UPPER 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 tri- 

 angular form. 



r w TWENTY ONE VELARS 



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. 



