THE FOOT. 277 



to tlie liornj sole, posteriorly to the horiij bars, and at the 

 posterior angles are continuous with the coronary frog band. 

 The posterior margin becomes very thin, blending with the 

 epidermis of the skin of the heels. The frog bulges oa the 

 ground surface of the foot, presenting anteriorly a rounded 

 angle or apex, and posteriorly, at the base, two rounded 

 prominences termed the bulbs, separated by the cleft, which 

 extends more than half the length of the frog in a forward 

 direction, being widest posteriorly, terminating in a point 

 anteriorly on the ground surface. The bulbs of the froo- 



are separated from the bars by the commissures, deep fis- 

 sures readily noticeable. The u]3per surface of the frog is 

 the exact counterpart of the lower, presenting centrally a 

 peculiar high prominence, terminating superiorly in a 

 rounded point, which fits into the cleft of the fibrous frog 

 (covered by its vascular coat) . This is termed the frog- 

 stay or peak, and on either side of it lies a concavity, 

 widest posteriorly, by its elevated outer margin blending 

 with the bars and sole. The two concavities run together 

 anteriorly, terminating in a point. This surface presents 

 small foramina for the delicate papillae of the sensitive 

 frog, least marked on the most prominent portions. The 

 fibres of the frog run obliquely downwards and forwards. 

 The colour of the hoof, in general, depends upon that of 

 the sensitive structure by which it is 2)i'oduced ; thus, in 

 horses with white coronets it is generally white, but any 

 coloration of the coronet is marked by corresponding colour 

 of the hoof below this point, extending from above towards 

 the ground surface, varying in length in direct proportion 

 to the superficiality, or otherwise, of the pigmentary 

 deposit. 



The hoof of the fore foot is marked by the roundness of 

 the plantar surface, broken posteriorly by the space for the 

 frog ; also by the obliquity of its walls, which are thickest 

 at the toe, and decrease in thickness towards the heels. 

 The distances from the centre of the toe to the extremity 

 of each heel should be equal, and also equal to the broadest 

 transverse diameter. The inner half of the sole is generally 

 smaller and narrower than the outer ; the inner quarter is 

 the most upright, and is thinner in the wall than the 

 outer. 



The hind hoof is ovoid, having its long diameter from 

 behind forwards. It is wide at the posterior part of the 



