256 THE ARTISTIC ANATOMY OF ANIMALS 



The inferior surface is concave, and thus forms a sort of 

 vault, more or less deep, according to the individual. The 

 sole has a scaly, laminated aspect. 



We have seen (Fig. 93, and p. 249) that on the inferior sur- 

 face of the claws of carnivora is found a small interval which 

 is filled by a plate of a more friable homy substance, to which 

 has been given the name of the plantar nail. It seems to us 

 that there is an interesting relationship between the said 

 plantar nail and the sole which we have just been studying. 



Indeed, these two horny structures appear to be homolo- 

 gous. Is not the lamina of the claw comparable to the 



Fig. 100. 



EJk.C. 

 -Inferior Surface of a Fore-hoof of the Horse : Left Side. 



I, Internal border of the wall (toe) ; 2, wall ; 3, quarter ; 4, heel ; 5, 

 bar; 6, sole; 7, frog; 8, median cavity; 9, prominence of the frog; 

 10, lateral cavity. 



wall of the hoof ? And does not the interval which occurs 

 at the inferior part of this latter, and is fiUed by the sole, 

 recall that which, in extremely reduced form, is filled by 

 the plantar portion of the claws ? 



The frog (Fig. 100) is a mass of horn, in form of a wedge, 

 with its apex in front, which occupies the space limited 

 laterally by the recurved portions of the wall (the bars) and 

 the posterior border of the sole. 



It covers the plantar cushion previously described (p. 252) 

 and reproduces its form. 



