presents some very slight deviations from the ordinary horse, and
     the crowns of the grinding teeth are shorter.  Then comes the
     Protohippus, which represents the European Hipparion, having
     one large digit and two small ones on each foot, and the general
     characters of the forearm and leg to which I have referred.  But
     it is more valuable than the European Hipparion for the reason
     that it is devoid of some of the peculiarities of that
     form—­peculiarities which tend to show that the European
     Hipparion is rather a member of a collateral branch than a form
     in the direct line of succession.  Next, in the backward order in
     time, is the Miohippus, which corresponds pretty nearly with
     the Anchitherium of Europe.  It presents three complete
     toes—­one large median and two smaller lateral ones:  and there
     is a rudiment of that digit which answers to the little finger of
     the human race.

      “The European pedigree of the horse stops here; in the America
     Tertiaries, on the contrary, the series of ancestral equine forms
     is continued into the Eocene formations.  An older Miocene form,
     called Mesohippus, has three toes in front, with a large
     splint-like rudiment representing the little finger; and three
     toes behind.  The radius and ulna, the tibia and fibula, are
     distinct, and the short crowned molar teeth are Anchitherioid
     in pattern.

      “But the most important discovery of all is the Orohippus
     which comes from the Eocene formation, and is the oldest member
     of the equine series yet known.  Here we find four complete toes
     on the front limb, three toes on the hind limb, a well-developed
     ulna, a well-developed fibula, and short-crowned grinders of a
     simple pattern.

      “Thus, thanks to these important researches, it has become
     evident that, so far as our present knowledge extends, the
     history of the horse type is exactly and precisely that which
     could have been predicted from a knowledge of the principles of
     evolution; and the knowledge we now possess justifies us
     completely in the anticipation that, when the still lower Eocene
     deposits, and those which belong to the Cretaceous period have
     yielded up their remains of ancestral equine animals, we shall
     find, first, a form with four complete toes and a rudiment of the
     innermost or first digit in front, with probably a rudiment of
     the fifth digit in the hind foot; while, in the older forms, the
     series of digits will be more and more complete until we come to
     the five-toed animals, in which, if the doctrine of evolution is
     well founded, the whole series must have taken its origin.”