DENTITION. 



135 



the tusks arc much grown, but do not arrive at maturity 

 until the age of six years. The title of colt has now 

 merged into that of horse, and that of filly into mare. 



SIX YEARS OLD. 

 At six years old the " mark " in the centre teeth 

 is obliterated ; a deep shade stains the teeth ; but, gene- 



rally speaking, the long black cavity is extinct. The 

 surfaces of the lateral teeth are much worn, and the 

 edges of the outer nippers are becoming smooth. The 

 tusks have now attained their full growth, and are 

 nearly an inch in length. Their outer surfaces are 

 round and convex, having the edges and points sharp. 

 The inner surfaces are partially concave and grooved. 



