Now while these changes in the toes were going on, the space between the front teeth and eye-teeth gradually increased, till we arrive at the large gap now seen in the horse and ass (see Fig. 67). The chief bone of the fore arm (radius) increased in size, and the other bone (ulna) became joined to it, and the same in the hind leg. The brain increased in size mainly in the front part, and the body grew much larger, improving in form and build, till the long, slender, flexible legs became the perfection of running and galloping limbs such as we find in the zebra of to-day, poised upon a strong jointed toe, with its last joint broadened into a firm pad, and covered with a thick nail--the hoof. We have only to compare the well-proportioned leg of a horse with the thick, strong, clumsy leg of an elephant, to see, on the one hand, what a shapely and beautiful limb it has become; while, on the other hand, if we put it by the side of a giraffe’s leg, we must acknowledge at once that it is a far stronger and more serviceable limb than if it had gone to the other extreme. There can be no doubt that when the horse arrived at this point of the strong single hoof and well-shaped body, he had a wide range over the world, both Old and New; but curiously enough, while in Asia and Africa the tribe branched out into many forms, such as asses, quaggas and zebras, in America it died out, so that till we found the fossil-forms,[168] it was thought that no horses had ever been there till they were brought by the Spaniards. Meanwhile, in the Old World, they must have led as free and joyous a life as those horses do now which have run wild in Tartary and America, galloping, frolicking, feeding, and neighing to each other with delight, as they roamed over the wide plains in troops of thousands, for solitary wanderers they would soon have fallen a prey to wolves or jaguars; and if the mothers wished to protect their foals they had to learn to follow one leader and act together in time of danger. “A thousand horse, the wild, the free, Like waves that follow o’er the sea, Headed by one black mighty steed Who seemed the patriarch of his breed,” they grew accustomed, as generations passed on, to unite against their common foes, placing the mares and their foals in the centre when attacked, while the fathers met the enemy with hoofs and teeth. And so they became intelligent and tractable even in their wild state, to those of their own kind, and laid the foundation of those noble qualities of which man now reaps the benefit.