The _pectoral_ (Fig. 30) pattern lies over the great fleshy masses formed by the pectoral muscles, which draw the fore-limbs upwards and inwards in conjunction with others in the actions of flexion and extension of these limbs. The patterns, A. B. C., are wide expansions of reversed hair beginning in the whorl (A), extending (B) upwards and terminated in a crest (C). This pattern is, like the frontal, invariably present in a domestic horse, and is shared by many other ungulates such as deer and antelopes, as mentioned in the appendix of a small book[49], I published in 1901. But in none is it so striking or definite as in the horse. The contractions of these pectoral muscles and their jolt at each step are easily observed in a trotting horse. It is interesting to compare this pattern on the horse’s pectoral region with what is found on the closely allied ass and mule. In the horse it is long and wide and never absent, and is especially well-developed in high-stepping horses whether cart-horses or others selected because of their high action in trotting. Its size, indeed, is a measure of the activity of the pectoral muscles and flexors of the fore-limb. In the ass it is often absent, and, when it is present, it is rudimentary; in the mule it is more frequently present than in the ass, but does not approach the pattern of the horse for size. These degrees of development in horse, ass and mule correspond closely with the locomotive habits of the three animals. [49] _Use-Inheritance._ A. & C. Black. _Direction of Hair._ The _inguinal_ (Fig. 31) pattern is one which the most casual observer of a horse cannot fail to notice, and it is so graceful in its shape as to add to the many beauties of its possessor. But in spite of this no breeder of horses has ever taken this pattern as one of the “points” of the animal, so that here again selection, even of the artificial kind, has had no share in its development. It is but a by-product of the locomotive life of the horse, and a very ancient character, for it is present in Przewalski’s horse, a probable ancestor of Equus Caballus. A domestic horse without this pattern would be a freak of Nature. It occurs in _equus hemionus_, the Thibetan wild ass, but not in _zebras_ or in the _quagga_.