602 



THE EXTERIOR OF THE HORSE. 



longer, larger, not so white, deprived of a neck between the root and the crown, 

 and have a wide gutter on their anterior face. 



Form. Their general form, always more regular in the pincers than in the 

 intermediates, and in the latter more so than in the corners, is that of an irreg- 

 ular cone, whose base, flattened from before to behind, corresponds to the free 

 extremity of the tooth, while the summit, depressed from side to side, corre- 

 sponds to the root. 



This double flattening of. the two extremities of the tooth necessarily implies 

 an intermediary zone more or less trifacial. 



The incisor tooth is, besides, curved in the direction of its length, which is 

 most marked in the pincers and least in the corners ; its long axis appears more 

 or less twisted upon itself from side to side, particularly at the level of the root. 

 This is most apparent in the intermediates and the corners. In order to facilitate 

 the description we will recognize in each incisor (Fig. 276) : 



FIG. 276. Unworn inferior pincer of the second dentition. 

 A. Posterior face. | B. Anterior face. | C. Profile. 



Two faces : the one anterior, the other posterior. 



Two borders : external and internal. 



Finally, two extremities : the crown, or free portion, and the root, or incased 

 portion. 



1st. Faces. The anterior face, wider at the crown than at the root, is 

 almost flat transversely and convex in the direction of its length. It contains a 

 longitudinal gutter, which is more marked on the crown than on the root. 



The superior incisors (Fig. 277), always wider and more curved, sometimes 

 have two grooves on the anterior face instead of one. 



The posterior face, rounded transversely, is concave from the summit to the 

 base ; its width and its curvature are more pronounced in the superior incisors. 



2d. Borders. The internal border is thicker than the external; each of 

 them, separating the two faces, augments in width from the base to the summit 



