THE DOMESTIC nORSE. 197 



■evidence whereby the age of a colt or horse is de- 

 termined. At the end of a year the fourth grinder 

 appears above and below, and the fifth at the end 

 of the second year, and then the first dentition is 

 complete. When three years old, the central nip- 

 pers in both jaws make room for a larger pair in 

 each, and are the first of the permanent set; six 

 months after, a second pair extrude the former on 

 each side of the first permanent ; and at four and a 



half the last set will be supplied, all distinctly 

 bearino: the mark : at five this mark begins to be 

 effaced by the wearing of the two first pair, and 

 the tushes or cuspidate teeth are exposed, leaving a 



