All breeders of fancy stock, particularly of pigeons and poultry, recognize the tendency of animals to revert to the forms whence they were derived and reproduce some character of a distant ancestor; to "throw back," as the breeders term it. If now, instead of reproducing a trait or feature possessed by some ancestor a score, a hundred, or perhaps a thousand years ago, there should reappear a characteristic of some ancestor that flourished 100,000 years back, we should have a seeming abnormality, but really a case of reversion; and the more we become acquainted with the structure of extinct animals and the development of those now living, the better able are we to explain these apparent abnormalities. Bearing in mind that the two splint bones of the horse correspond to the upper portions of the side toes of the Hippotherium and Mesohippus, it is easy to see that if for any reason these should develop into toes, they would make the foot of a modern horse appear like that of his distant ancestor. While such a thing rarely happens, yet now and then nature apparently does attempt to reproduce a horse's foot after the ancient pattern, for occasionally we meet with a horse having, instead of the single toe with which the average horse is satisfied, one or possibly two extra toes. Sometimes the toe is extra in every sense of the word, being a mere duplication of the central toe; but sometimes it is an actual development of one of the splint bones. No less a personage than Julius Caesar possessed one of these polydactyl horses, and the reporters of the _Daily Roman_ and the _Tiberian Gazette_ doubtless wrote it up in good journalistic Latin, for we find the horse described as having feet that were almost human, and as being looked upon with great awe. While this is the most celebrated of extra-toed horses, other and more plebeian individuals have been much more widely known through having been exhibited throughout the country under such titles as "Clique, the horse with six feet," "the eight-footed Cuban horse," and so on; and possibly some of these are familiar to readers of this page.