292 THE HORSE. 



The front is tte toe, the back the heel, and thi iutermediate part 

 the quarter on each side. It is said by Bracy Clark to be a 

 segment of a cylinder, but it is really narrower at the top than at 



the bottom, and it should rather be described as a section of a 

 truncated cone. When examined from the side, the anterior sur- 

 face should form an angle of about forty-five degrees with the line 

 of the sole, and the upper edge or coronary band should join the 

 sole, so as to leave a moderate substance at the heel ; for if too 

 great the foot does not expand, and is liable to disease from that 

 cause ; or if too thin and narrow, the foot is weak and gives way 

 downwards, ending in a convexity of the sole instead of the 

 reverse. The front of the crust is rather more than half an inch 

 in thickness, and in a strong foot of average size gradually 

 diminisliiiig to the quarters, at 

 the back of which it is generally 

 barely a quarter of an inch 

 thick, especially at the inner of 

 the two. This proportion is 

 however confined to the ft re 

 foot, for in the hind there is 

 little difference between the toe 

 and quarters in point of thick- 

 ness. The superior border, or 

 coronary band, is marked by its 

 whitish color. On its external 

 )oT surface it resembles the crust 

 below ; but internally it differs 

 ill being smoothly excavat<;d. 



rtO. 15. — THE UNDER SCRFACE 



A. Cleft of frog. 



