the human hand contains one overgrown 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 fore-arm bone
is composed of the coalesced 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 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, good cutting instruments and powerful and
lasting crushers are needful. Accordingly, the twelve cutting teeth of a
horse are close-set and concentrated in the fore-part of its mouth, like