XIII 
THE GEOLOGICAL EVIDENCES OF EVOLUTION 
385 
what lies below the horse’s ‘ knee ’ thus corresponds to the 
middle finger in ourselves, what has become of the four other 
fingers or digits ? We find in the places of the second and 
fourth digits only two slender splintlike bones, about two- 
thirds as long as the cannon bone, which gradually taper to 
their lower ends and bear no finger joints, or, as they are 
termed, phalanges. Sometimes, small bony or gristly nodules 
are to be found at the bases of these two metacarpal splints, 
and it is probable that these represent rudiments of the first 
and fifth toes. Thus, the part of the horse’s skeleton which 
corresponds with that of the human hand, contains one over¬ 
grown middle digit, and at least two imperfect lateral digits; 
and these answer, respectively, 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, however, 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 forearm 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 forefoot. And, as in the forefoot, there 
are merely two splints to represent the second and the fourth 
toes. Sometimes a rudiment of a fifth toe appears to be 
traceable. 
“ The teeth of a horse are not less peculiar than its limbs. 
The living engine, like all others, must be well stoked if it is 
to do its work; and the horse, if it is to make good its wear 
and tear, and to exert the enormous amount of force required 
for its propulsion, must be well and rapidly fed. To this end, 
