he
web of life is welcome, but Dr. Wallace does not seem to have learned
the facts accurately. There is nothing "puzzling" about the Mesozoic
reptilian development; the depression of the land, the moist warmth,
and the luscious vegetation of the later Triassic and the Jurassic
amply explain it. Again, the only carnivores to whom they seem to have
supplied food were reptiles of their own race. Nor can the feeding of
the herbivorous reptiles be connected with the rise of the Angiosperms.
We do not find the flowering plants developing anywhere in those vast
regions where the great reptiles abounded; they invade them from some
single unknown region, and mingle with the pines and ginkgoes, while the
cyeads alone are destroyed.

The grasses, in particular, do not appear until the Cretaceous, and do
not show much development until the mid-Tertiary; and their development
seems to be chiefly connected with physical conditions. The meandering
rivers and broad lakes of the mid-Tertiary would have their fringes
of grass and sedge, and, as the lakes dried up in the vicissitudes of
climate, large areas of grass would be left on their sites. To these
primitive prairies the mammal (not reptile) herbivores would be
attracted, with important results. The consequences to the animals
we will consider presently. The effect on the grasses may be well
understood on the lines so usefully indicated in Dr. Wallace's book. The
incessant cropping, age after age, would check the growth of the larger
and coarser grasses give opportunity to the smaller and finer, and lead
in time to the development of the grassy plains of the modern world.
Thus one more familiar feature was added to the landscape in the
Tertiary Era.

As this fresh green carpet spread over the formerly naked plains,
it began to be enriched with our coloured flowers. There were large
flowers, we saw, on some of the Mesozoic cycads, but their sober yellows
and greens--to judge from their descendants--would do little to brighten
the landscape. It is in the course of the Tertiary Era that the mantle
of green begins to be embroidered with the brilliant hues of our
flowers.

Grant Allen put forward in 1882 ("The Colours of Flowers") an
interesting theory of the appearance of the colours of flowers, and it
is regarded as probable. He observed that most of the simplest flowers
are yellow; the more advanced flowers of simple families, and the
simpler flowers of slightly advanced families,