THE LIMBS OF THE HOESE 83 



outline, and may be divided into a body and two rami or cornua. Its 

 convex or greater border is connected with the wall by the compara- 

 tively soft and elastic layer of horn to which reference is made above. 



The free surface of the sole is more or less concave, the degree of 

 concavity depending in some measure on the breed of the animal; but 

 the hollow always contains flakes of horn that are in process of beino- 

 shed. The inner surface is pitted with small holes for the reception of 

 the papilla? of the solar matrix, and is convex in form witli the highest 

 point of the dome close to the apex of the " frog." The curvature of 

 the sole is greater in the pelvic than in the thoracic limb. 



Layer of pale horn _ 

 uniting wall and sole. 



Inflected part of ^ 

 wall (" bar"). 



Cruro-parietal groove. — 

 Intercrural groove 



— Sole. 



.ApeN of cuneus. 



__Crus of cuneus. 



Base of cuneus ("bulb"). 



Fig. 57. — Volar Aspect of the Hoof. 



3. The cuneus 1 or " frog" (cuneus ungulse) may be best described as 

 having four surfaces. The inner or upper surface presents two grooves, 

 converging and meeting in front, with an abruptly sloping projection 

 or spine (spina cunei unguke) between them. The whole of this 

 surface is pitted with minute holes into which the papillae of the 

 cuneate matrix are received. 



The free surface of the cuneus is triangular in form, and carries 

 two ridges or crura (crura cunei unguke) that converge and meet in 

 front at the apex (apex cunei ungulae). Between the crura is the deep 

 intercrural groove (sulcus intercruralis) corresponding in position to 

 the spine on the upper surface, and, therefore, deepest posteriorly, with 

 a rapidly shelving anterior part. The medial and lateral surfaces are 

 partly connected with the sole and the inflected parts of the wall, and 

 partly free where they help to bound the cruro-parietal grooves (sulci 



1 Cuneus [L.], a wedge. 



