sents 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 fro