EPIDERMIC PRODUCTS 



249 



of which is, in this case, turned towards the claws ; its 

 margin being sometimes strongly indented, it may also have 

 a trilobate form. It is on it that rest the metacarpo- 

 phalangeal or metatarso-phalangeal articulations, according 

 to the limb studied. The tubercle of the carpus, situated 

 at the level of the posterior surface of this latter, is less 

 important than the preceding, the region which it occupies 



'ii 



Fig. 93. — Claw of the Dog: 

 Inferior Surface. 



I , Horny lamina of the claw : 

 2, plantar nail ; 3, tubercle of 

 the corresponding digit. 



Fig. 94. — Left Hand of the Dog : In- 

 ferior Surface, Plantar Tuber- 

 cles. 



I, I, I, I, I, Tubercles of the fingers ; 

 2, plantar tubercle ; 3, tubercle of the 

 carpus. 



not reaching the ground during walking. But it is not to 

 be neglected from the point of view of external form, because 

 of the prominence which it produces. 



In the ungulates the terminal extremity of the limb is, 

 as we have above pointed out, enclosed in a homy envelope 

 which is no other than the hoof. 



We will first study the hoof of the horse — a hoof which 



