INTRODUCTION 



THEOLOGIANS AND NATURALISTS who were content to accept the book 

 of Genesis verbatim et literatim were formerly agreed that all animals 

 sufficiently distinct to constitute a species had a separate origin. No 

 scientific proof of this can of course be adduced. The structure of the 

 horse and the fossil remains by which his past can be traced afford 

 evidence of transmutation. 



The horse of to-day has rudimentary structures which in other animals 

 perform definite functions, but to him are useless or apparently so. 

 The study of paleontology leads to the supposition that the horse, as 

 we know him now, is the product of a very late period in the world's 

 history, but through fossil remains he may be traced back through the 

 pleistocene, the pliocene, the miocene into the eocene, beyond which 

 no fragmentary evidences exist upon which to build up an ancestor. 



The horse, as Sir W. H. Flower says in Modern Science, cannot be 

 treated of "as an isolated form, but as one link in a great chain, 

 one term in a vast series, one twig of a mighty tree : and to endeavour 

 to trace as far as our present knowledge permits what its relations are to 

 the rest, and by what steps of modification in its various parts it has 

 come to be the very singular and highly specialized animal we have now 

 before us, so distinct from all existing forms of life that in most of 

 the older zoological systems it was (at least associated only with some 

 very immediate allies, structurally almost identical) placed in an order 

 apart from all other mammals under the name of Solidungula, Solipedia, 

 or Monodactyla, the animal with the solid foot, or rather with a single 

 toe on each extremity." 



The genus Equus, family Equidce, include the ass and zebra, whose 

 organization differs only in minor details. 



