The Percheron horse

Abstract

Introduction: The most remote ancestor of the horse of which we have any knowledge is the Phenacodus, which is antecedent to all the horse series, the hog, the rhinoceros, and all the other series of hoofed animals. The Phenacodus belonged to the early Eocene period, had five digits on each limb and three phalanges on each digit, the ulna and fibula were entire and separate from respectively the radius and tibia, there was no interlocking of the carpal bones. There were twenty two teeth on each jaw, the incisors being small and with sharp edges, the canines were well developed in both male and female. There was no diastema between the canines and pre-molars. The molars had very short crowns each of which had six cusps, the skull and brain were small and the head was carried nearly on a line with the neck. Phenacodus resembled a wolf in appearance, was about forty two inches high and walked chiefly on his second, third and fourth toes, which were provided with small hoofs, the third toe being wider and longer than the others. He was active, had a long tail, powerful hind quarters and was probably omnivorous and inhabited swampy ground and low lying forests. The next higher form was the Eohippus of the lower Eocene period, which was about the size of a fox and inhabited Europe as well as America. The first digit was absent on all the limbs and there was only a vestige of the fifth on the hind limbs. The bones of the wrist were becoming interlocked as in the horse but the ulna and fibula were still complete and separate. In the structure of the teeth and feet the Eohippus indicates that the direct ancestoral descent of the modern horse had already separated from the other perissodactyles or odd toed Ungulates. The feed appears to have been succulent grasses. The following forms are believed to connect…