But these mammals of the early Tertiary are still of such a
patriarchal or ancestral character that the student of evolution
can dispense with their earlier phase. They combine in their
primitive frames, in an elementary way, the features which we now
find distributed in widely removed groups of their descendants.
Most of them fall into two large orders: the Condylarthra, the
ancestral herbivores from which we shall find our horses, oxen,
deer, elephants, and hogs gradually issuing, and the Creodonta,
the patriarchal carnivores, which will give birth to our lions
and tigers, wolves and foxes, and their various cousins. As yet
even the two general types of herbivore and carnivore are so
imperfectly separated that it is not always possible to
distinguish between them. Nearly all of them have the five-toed
foot of the reptile ancestor; and the flat nails on their toes
are the common material out of which the hoof of the ungulate and
the claw of the carnivore will be presently fashioned. Nearly all
have forty-four simply constructed teeth, from which will be
evolved the grinders and tusks of the elephant or the canines of
the tiger. They answer in every respect to the theory that some
primitive local group was the common source of all our great
mammals.
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