The Quagga was more striped than is sometimes represented in illustrations. According to Dr. Noack, from whose paper[160] upon the animal I quote here, the transverse stripes reached back as far as the buttocks; they were, however, completely absent from the legs. The animal is, as every one knows, probably completely extinct. In the year 1836 it was still abundant; in 1864 the last specimen ever exhibited was received by the Zoological Society. Mr. W. L. Sclater thinks that it may have survived in the Orange River Colony as late as 1878, but admits that any certainty is difficult, as it was frequently confounded by the Boers with Burchell's Zebra. Its rarity is emphasised by the fact that it is not mentioned in the recent work of that most skilful of hunters, Mr. F. Selous. Gaudry places the Quagga nearest of all living Equidae to the _Hipparion gracile_ of Pikermi. FOSSIL EQUIDAE.--The existing Equidae all belong to the genus _Equus_, though there are some who would (quite unnecessarily) divide off the Zebras as a genus _Hippotigris_. The genus _Equus_ itself goes back in time to the Pliocene, during which epoch there lived in India _E. sivalensis_, the same species according to some with the _E. stenonis_ of Europe. None of these species, Old World or New, are easily to be separated from _E. caballus_. But many names have been given to them. It is of course perfectly conceivable that they may have differed among themselves as much as do the existing Zebras and Asses, the separation of which would be hardly possible did we know their bones only. There are, however, extinct genera, undoubtedly related so closely to _Equus_ as to be placed in the same family, though clearly separable as genera. _Hipparion_ is one of these genera; its remains are known from Europe, Asia, and North Africa, from beds of Miocene and Pliocene times. A large number of different species have been described. It was a beast of about the size of a Zebra. The principal characters are that each foot has three toes, of which, however, the two side ones are smaller than the central toe. There is a marked round fossa on the maxillary bone, a feature shared by the South American _Onohippidium_.[161] The pattern of {247} the molar teeth is, too, a little different from that of _Equus_. _Protohippus_ of the North American Pliocene is also three-toed, but the two additionally-developed toes are smaller than in _Hipparion_. Other forms are dealt with below in connexion with the ancestry of Perissodactyles. It is a curious fact about _Hipparion_, which is not now regarded as on the direct line of equine descent, that the edges of the enamel plates of the molars may show a complicated folding very like that presented by that clearly terminal form of Perissodactyle life, the gigantic _Elasmotherium_. This is indicative of high specialisation, which ended in extinction.