118 LECTURES ON EVOLUTION ill 



corresponds with that of the human hand, con- 

 tains one overgrown middle digit, and at least 

 two imperfect lateral digits ; and these answer, re- 

 spectively, to the third, the second, and the fourth 

 fingers in man. 



Corresponding modifications are found in the 

 hind limb. In ourselves, and in most quadrupeds, 

 the leg contains two distinct bones, a large bone, 

 the tibia, and a smaller and more slender bone, 

 the fibula. But, in the horse, the fibula seems, 

 at first, to be reduced to its upper end ; a short 

 slender bone united with the tibia, and ending in 

 a point below, occupying its place. Examination 

 of the lower end of a young foal's shin-bone, how- 

 ever, shows a distinct portion of osseous matter, 

 which is the lower end of the fibula ; so that the, 

 apparently single, lower end of the shin-bone is 

 really made up of the coalesced ends of the tibia 

 and fibula, just as the, apparently single, lower 

 end of the fore-arm bone is composed of the coal- 

 esced radius and ulna. 



The heel of the horse is the part commonly 

 known as the hock. The hinder cannon bone 

 answers to the middle metatarsal bone of the 

 human foot, the pastern, coronary, and coffin 

 bones, to the middle toe bones ; the hind hoof to 

 the nail ; as in the fore-foot. And, as in the fore- 

 foot, there are merely two splints to represent the 

 second and the fourth toes. Sometimes a rudi- 

 ment of a fifth toe appears to be traceable. 



