740 EXAMINATION FOE AGE. 



replaced, in due course, by permanent teeth. The molars are 

 not preceded by milk teeth, and are consequently permanent. We 

 frequently find in the mouths of foals, very small, pointed teeth, 

 where the canines subsequently appear. Some authorities regard 

 these minute teeth as rudimentary milk tushes; but they are so 

 insignificant in size that we may, practically speaking, even while 

 conceding this jDoint, look upon the canines as permanent teeth. 



The typical dental formula of the mammalia (animals which 

 suckle their young) is (taking one side of each jaw) : — 



3 1 4 3 



incisors — canines — premolars — molars — = 44. 

 3 1 4 3 



The teeth of the ancestors of the horse, from the pliohippus 

 upwards, conformed to this arrangement; but the horse of the 

 present day has, as a rule, only 3 premolars (2nd, 3rd, and 4th) ; 

 although in embryo, as observed by Professor Cossart Ewart, the 

 1st premolar is always present. It is occasionally found in the 

 upper Jaw (Figs. 224 and 236), seldom in the lower jaw, and, as 

 remarked by Goubaux and Barrier, very rarely in both jaws. 

 These teeth, which are popularly called " wolfs teeth," are of 

 comparatively small size and have only one root. Comevin and 

 Lesbre, who maintain that these teeth are always to be found 

 in the upper jaw, state that they usually appear at the age of 

 5 or 6 months ; that they generally fall out along with the second 

 milk premolar, at about the age of 2|- years ; and are not re- 

 placed. They sometimes remain permanently in the jaw. They 

 are vestigal, and not supernumerary teeth. 



The two front incisors are termed central incisors; the next 

 pair, lateral incisors; and the two farthest back, corner incisors. 

 The premolars and molars are numbered respectively, 1, 2, 3, 4, 

 and 1, 2, 3, from the front backwards. 



Omitting the first premolar on account of its insignificant 

 size and inconstant appearance, we may state that a horse with a 

 "full mouth" has 40 permanent teeth, namely, 12 incisors (6 in 

 each jaw), 4 canines, and 24 ba<3k teeth (6 premolars and 6 

 molars in each jaw) ; and that a mare with a " full mouth " has 

 36 teeth. Consequently, their respective permanent dental 

 formulie are : — 



3 13 3 3 3 3 



i — c — pm — m — = 40, and i — pm — m — = 36. 

 3 13 3 3 3 3 



The milk dental formula of both horses and mares is: — 



3 3 



1 — pm 



24. 



