DISSECTION OF THE ANTERIOR LIMB. 37 



inferior border embraces the sole, and in the unshod animal comes 

 into contact with the ground. The wall is here united to the sole 

 by a stratum of unpigmented horn, which appears on the under 

 surface of the foot as a well-defined line, termed the " white line." 



The wall is thicker at the toe than at the quarters or heels ; and 

 in each of these areas it is thicker on the outside than in the corre- 

 sponding area on the inside. 



The Bars. These are the reflected terminations of the heels, and 

 if. the foot be turned up the continuity will be distinctly seen. 



The Outer Surface of the bar, which is here seen, slopes towards the 

 frog, and bounds outwardly the lateral lacuna of that body. It shows 

 an inferior border, which runs towards the centre of the sole, but stops 

 a little behind the point of the frog. The bars are also seen in the 

 interior of the hoof, where they show an internal surface bearing horny 

 laminre like those of the wall. The superior border of the bars is 

 included between the frog and the sole, and blended with them. 



The Sole presents an inferior face, which is vaulted, and this in- 

 dependently of any paring to which the foot may have been subjected, 

 as the horn of which it is composed exfoliates so as to give it this 

 configuration naturally. The superior face is somew 7 hat convex, and 

 has a punctated appearance similar to /that already seen in the cutigeral 

 groove. The minute holes lodge the papillae of the so-called sensitive 

 sole, which is the horn-secreting structure of this region. Anteriorly 

 the sole presents a convex border, which unites it intimately to the 

 lower border of the wall at the " white line." Posteriorly it has a 

 deep V-shaped indentation, into the central point of which the frog 

 penetrates, while behind that on each side it is related to the bar. 



The sole of the hind hoof is distinguished from that of the fore by 

 being more vaulted, and by being more pointed (less circular) at the 

 toe, this latter difference affecting also the form of the wall in the same 

 region. The outer edge of the sole is more convex than the inner, which 

 enables one to distinguish readily between a right and a left hoof. 



The Frog. This is a distinctly elastic mass of horn which, in a state 

 of nature, projects sufficiently to come into contact with the ground, 

 and thus give the animal a secure foothold. Its inferior surface shows 

 posteriorly a shallow cleft, or depression, termed the median lacuna. 

 The lateral lacunce lie at the sides of the frog, the outer boundary of 

 each lacuna being formed by the bar. The superior, surface shows, 

 vertically over the median lacuna, a projection termed the frog-stay. 

 On each side of the frog-stay this surface is depressed, and the whole 

 is moulded on the plantar cushion. This surface is punctated, and 

 the papillae of the plantar cushion are received into the minute 

 apertures. The posterior extremity, or base, of the frog consists of 

 two rounded eminences — the bulbs, or glomes — separated from each 



