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. With them are ancestral forms of Edentates (sloths, etc.) and
Insectivores (moles, etc.), side-branches developing according to their
special habits; and before the end of the Eocene we find primitive
Rodents (squirrels, etc.) and Cheiroptera (bats).

From the description of the Tertiary world which we have seen in the
last chapter we understand the rapid evolution of the herbivorous
Condylarthra. The rich vegetation which spreads over the northern
continents, to which they have penetrated, gives them an enormous
vitality and fecundity, and they break into groups, as they increase
in number, adapted to the different conditions of forest, marsh, or
grass-covered plain. Some of them, swelling lazily on the abundant food,
and secure for a time in their strength, become the Deinosaurs of their
age, mere feeding and breeding machines. They are massive, sluggish,
small-brained animals, their strong stumpy limbs terminating in broad
five-toed feet. Coryphodon, sometimes as large as an ox, is a typical
representative. It is a type fitted only for prosperous days, and these
Amblypoda, as they are called, will disappear as soon as the great
carnivores are developed.

Another doomed race, or abortive experiment of early mammal life, wer