Fig. 102.—Third Phalanx of the Horse: Left Posterior Limb, Inferior View.
1, External border; 2, internal border; 3, semilunar crest; 4, 4, re-entrant processes.
As an indispensable complement to the study which we have just made, it is necessary to add that the hoofs of the fore-limbs and those of the hind ones present differences of form which cannot be ignored—differences which we are already able to conjecture by looking at the respective third phalanges which terminate those limbs, and especially at their inferior surfaces ([Figs. 101], [102]).
The hoofs of the fore-limbs (see [Fig. 100]), viewed on their plantar surface, are more rounded than those of the hind-limbs ([Fig. 103])—so that their external contour may be compared to a semicircle—whilst the hind-hoofs, which are narrow and of more oval shape, rather recall by their form the aspect of an ogive.
Fig. 103.—Inferior Surface of a Hind-hoof of a Horse: Left Side.
1, External border; 2, internal border.
This seems to result from the fact that the fore-limbs support the more considerable part of the weight of the animal. The best proof which can be given of this overweighting is the eagerness with which very often, when a horse is stopped near the edge of a footpath, for example, he places his fore-feet on the latter. In thus raising his fore-quarters, he throws part of his weight backwards, and in this way relieves his fore-limbs.