596 THE EXTERIOR OF THE HORSE. 



The most anterior are called incisors, P, M, C, destined to seize, 

 tear, and cut the aliment. 



Then come the tusks, canine teeth, or fangs, Or, whose role is to tear. 



Finally, those which occupy the posterior part of the mouth are 

 the molars, MC, MP, which serve to crush, in the manner of a mill- 

 stone. 



Concerning their disposition in the jaws, the teeth form a parabolic 

 curve designated under the name dental arcade. The dental arcades, 

 two in number and distinguished as superior and inferior, are composed 

 of three parts : one anterior and two lateral. 



The incisors, six in number in each jaw, occupy the anterior part, 

 and describe, as a whole, a transverse semicircle convex in front. 



The molars, situated behind and upon the lateral parts, are twelve 

 in number in each jaw : six on the right side and six on the left 

 side. 



But immediately behind the incisive arcade, between it and the 

 molars, exists on each jaw an asymmetrical interval called the inter- 

 dental space, upon the course of which the canines or tusks are situated. 

 The bar, as we already understand it, is the name given to the region 

 of the interdental space situated behind the inferior canine tooth. In 

 the mare, in which the canines are more or less aborted, the interdental 

 space is commonly uninterrupted ; the bar is consequently longer than 

 in the male. 



We count, consequently, in the adult, in each jaw and on each side, 

 3 incisors, 1 canine, and 6 molars, making in all 40 or 36 permanent 

 teeth, according to the sex. 



During the first period of life the teeth are not quite so numerous : 

 only three molars exist on each side, in each jaw, and the tusks are 

 usually wanting. The dentition of the colt, therefore, comprises 12 

 incisors and 12 molars, or a total of 24 teeth, whose duration is alto- 

 gether transient. 



Let us add that Daubenton, Lafosse, Tenon, and Girard l have said 

 that the teeth are sometimes 44 in number ; in this case there are super- 

 numerary premolars ; we will again revert to these. 



1 Daubenton, see Histoire naturelle g6nrale et particuliere avec la description du cabinet 

 du Roi, par Buffon. Edition in-4o de rimprirnerie royale, t. iv., Paris, 1763, p. 334. 



Lafosse, Cours d'hippiatrique ou traite complet de la m^decine des chevaux, in-folio, Paris, 

 1772, p. 24. 



Tenon, Second essai d'eiude, par gpoques, des dents molaires du cheval. Eead and depos- 

 ited with the secretary of the Institute the 16th day of the fourth month in the fifth year (French 

 calendar). This essay has been published in the Memoirs of the National Institute of Sciences 

 and Arts for the fourth year of the Republic (Sciences mathematiques et physiques), p. W). 



J. Girard, Traite de 1'age du cheval, 3e 6d., Paris, 1834, p. 35. 



