acarpal and metatarsal bones; and, attached to the
extremity of each, is a digit with three joints of the same general
character as those of the middle digit, only very much smaller. These
small digits are so disposed that they could have had but very little
functional importance, and they must have been rather of the nature of
the dew-claws, such as are to be found in many ruminant animals. The
_Hipparion,_ as the extinct European three-toed horse is called, in
fact, presents a foot similar to that of the American _Protohippus_
(Fig. 9), except that, in the _Hipparion,_ the smaller digits are
situated farther back, and are of smaller proportional size, than in the
_Protohippus._

The ulna is slightly more distinct than in the horse; and the whole
length of it, as a very slender shaft, intimately united with the
radius, is completely traceable. The fibula appears to be in the same
condition as in the horse. The teeth of the _Hipparion_ are essentially
similar to those of the horse, but the pattern of the grinders is in
some respects a little more complex, and there is a depression on the
face of the skull in front of the orbit, which is not seen in existing
horses.

In the earlier Miocene, and perhaps the later Eocene deposits of some
parts of Europe, another extinct animal has been discovered, which
Cuvier, who first described some fragments of it, considered to be a
_Palaeotherim._ But as further discoveries threw new light upon its
structure, it was recognised as a distinct genus, under the name of
_Anchitherium._

In its general characters, the skeleton of _Anchitherium_ is very
similar to that of the horse. In fact, Lartet and De Blainville called
it _Palaeotherium equinum_ or _hippoides;_ and De Christol, in 1847, said
that it differed from _Hipparion_ in little more than the characters of
its teeth, and gave it the name of _Hipparitherium._ Each foot
possesses three complete toes; while the lateral toes are much larger in
proportion to the middle toe than in _Hipparion,_ and doubtless rested
on the ground in ordinary locomotion.

The ulna is complete and quite distinct from the radius, though firmly
united with the latter. The fibula seems also to have been complete. Its
lower end, though intimately united with that of the tibia, is clearly
marked off from the latter bone.

There are forty-four teeth. The incisors have no strong pit. The canines
seem to have been well developed in both sexes. The first of t