THE II EAD AND NECK 



131 



week they are fairly up in the mouth. The first and 

 second molars come into place about the same time. 

 Between the first and second month the second (lateral) 

 incisors appear, then the third molar, and finally 

 (at about nine months) the third (corner) incisors, 

 which complete the milk dentition. Of the permanent 

 teeth, the first true molar appears about the end of the 

 first year, followed by the second molar before the end 

 of the second year. These teeth are thus in place 

 before any of the milk teeth have been shed. At about 

 two and a half years the first premolar replaces its pre- 

 decessor. Between two and a half and three years the 

 first permanent incisor appears. At three years the 

 second and third premolars and the third true molar 

 have appeared, at from three and a half to four years 

 the second incisor, at four to four and a half years the 

 canine, and finally, at five years, the third (corner) 

 incisor, completing the permanent dentition. Up to 

 this period the age of the horse is clearly shown by the 

 condition of its dentition, and for some years longer 

 indications can be obtained from the wear of the incisor 

 teeth, 1 though this depends to a certain extent upon 

 the hardness of the food and other accidental circum- 

 stances. 



1 These are very fully described and illustrated in a pamphlet 

 called Dentition as indicative of the Age of the Animals of the Farm, 

 by Professor G. T. Brown, 2nd edit. 1889. 



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