196 THE STKUCTUKE OF THE HOUSE. 



almost the center of the under surface of the toe at 

 the apex of the plantar cushion or frog. This part 

 of the hoof-matrix (Fig. 25, 13), which from its 

 structure is called the " podophyllous " or "lamina!" 

 tissue, is deeper from above downwards in front, and 

 gradually gets shallower posteriorly, the incurved 

 ends (which correspond to the " bars " of the horny 

 hoof) thinning almost to nothing at their termina- 

 tions. Instead of being covered with irregularly- 

 scattered villi, like the coronary cushion and frog, its 

 surface is raised into very numerous (five or six hun- 

 dred altogether) longitudinal, parallel, fine leaf-like 

 ridges or " lamella?," all extremely vascular and sen- 

 sitive, and being themselves covered on each side 

 with numerous other finer ridges, set obliquely upon 

 them a most complex and delicate apparatus, enor- 

 mously increasing the superficial area of the kerato- 

 genous membrane. This region of the matrix of the 

 horse's hoof corresponds to the flat surface below the 

 human nail, and the longitudinal ridges observed in 

 the latter are obviously the same structures as the 

 lamellae of the horse's foot, only in a very slightly 

 developed condition. 



3. The third part of the matrix of the hoof is that 

 portion of the vascular derm which covers the lower 

 surface of the pedal bone, or the " sole " of the foot. 

 It is crescentic in shape, and bordered all round by 



