lection may choose
yet higher types. We turn now to consider the animal population which,
directly or indirectly, fed upon it, and grew with its growth. To the
reptiles, the birds, and the mammals, we must devote special chapters.
Here we may briefly survey the less conspicuous animals of the Mesozoic
Epoch.

The insects would be one of the chief classes to benefit by the renewed
luxuriance of the vegetation. The Hymenopters (butterflies) have not yet
appeared. They will, naturally, come with the flowers in the next
great phase of organic life. But all the other orders of insects are
represented, and many of our modern genera are fully evolved. The giant
insects of the Coal-forest, with their mixed patriarchal features, have
given place to more definite types. Swarms of dragon-flies, may-flies,
termites (with wings), crickets, and cockroaches, may be gathered from
the preserved remains. The beetles (Coleopters) have come on the scene
in the Triassic, and prospered exceedingly. In some strata three-fourths
of the insects are beetles, and as we find that many of them
are wood-eaters, we are not surprised. Flies (Dipters) and ants
(Hymenopters) also are found, and, although it is useless to expect to
find the intermediate forms of such frail creatures, the record is of
some evolutionary interest. The ants are all winged. Apparently there
is as yet none of the remarkable division of labour which we find in the
ants to-day, and we may trust that some later period of change may throw
light on its origin.

Just as the growth of the forests--for the Mesozoic vegetation has
formed immense coal-beds in many parts of the world, even in Yorkshire
and Scotland--explains this great development of the insects, they would
in their turn supply a rich diet to the smaller land animals and flying
animals of the time. We shall see this presently. Let us first glance at
the advances among the inhabitants of the seas.

The most important and stimulating event in the seas is the arrival of
the Ammonite. One branch of the early shell-fish, it will be remembered,
retained the head of its naked ancestor, and lived at the open mouth of
its shell, thus giving birth to the Cephalopods. The first form was
a long, straight, tapering shell, sometimes several feet long. In the
course of time new forms with curved shells appeared, and began to
displace the straight-shelled. Then Cephalopods with close-coiled
shells, like the nautilus, came, and--such