* Many varieties, differing in form, size, color, gait, speed, etc., are known, but all are believed to have been derived from the same original species. It is supposed to have been a native of the plains of Central Asia, but the wild species from which it was derived is not certainly known. The feral horses of America are domestic horses that have run wild; and it is probably true that most of those of Asia have a similar origin. Some of the true wild Asiatic horses do, however, approach the domestic horse in several characteristics.
Several species of fossil (Equus) are known from the later Tertiary formations of Europe and America. The fossil species of other genera of the family Equidæ are also often called horses, in general sense.

The armies were appointed, consisting of twenty-five thousand horse and foot. Bacon.