VII.—Studies on the Development of the Horse. I. The Development during the Third Week.

Abstract

Soon after the publication ofThe Origin of Speciesit was realised by Huxley and others that convincing evidence of the fact of evolution might be obtained by a systematic investigation of the ancestral history and development of the Equidæ. From studying material in the British and other Museums Huxley announced at the end of the ’sixties that he believed “the Anchitherium, the Hipparion and the modern horses constitute a series in which the modifications of structure coincide with the order of chronological recurrence in the manner in which they must coincide if the modern horses really are the result of the gradual metamorphosis in the course of the Tertiary epoch of a less specialised ancestral form.” But this conclusion was soon profoundly modified. When in 1876 Huxley had the opportunity of examining the Yale and other collections of the fossil horses of America, he was satisfied that “we must look to America rather than to Europe for the original seat of the Equine series,” and “that the European Hipparion is rather a member of a collateral branch than a form in the direct line of succession.”