dragons of the fairy tale. They
spread over the whole earth from Australia to the Arctic circle. Then
the earth seems to grow impatient of their dominance, and they shrink
towards the south, and struggle in a diminished territory. The colossal
monsters and the formidable dragons go the way of all primitive life,
and a ragged regiment of crocodiles, turtles, and serpents in the
tropics, with a swarm of smaller creatures in the fringes of the warm
zone, is all that remains, by the Tertiary Era, of the world-conquering
army of the Mesozoic reptiles.

They had appeared, as we said, in the Permian period. Probably they
had been developed during the later Carboniferous, since we find
them already branched into three orders, with many sub-orders, in the
Permian. The stimulating and selecting disturbances which culminated in
the Permian revolution had begun in the Carboniferous. Their origin is
not clear, as the intermediate forms between them and the amphibia are
not found. This is not surprising, if we may suppose that some of the
amphibia had, in the growing struggle, pushed inland, or that, as the
land rose and the waters were drained in certain regions, they had
gradually adopted a purely terrestrial life, as some of the frogs have
since done. In the absence of water their frames would not be preserved
and fossilised. We can, therefore, understand the gap in the record
between the amphibia and the reptiles. From their structure we gather
that they sprang from at least two different branches of the amphibia.
Their remains fall into two great groups, which are known as the Diapsid
and the Synapsid reptiles. The former seem to be more closely related to
the Microsauria, or small salamander-like amphibia of the Coal-forest;
the latter are nearer to the Labyrinthodonts. It is not suggested that
these were their actual ancestors, but that they came from the same
early amphibian root.

We find both these groups, in patriarchal forms, in Europe, North
America, and South Africa during the Permian period. They are usually
moderate in size, but in places they seem to have found good conditions
and prospered. A few years ago a Permian bed in Russia yielded a most
interesting series of remains of Synapsid reptiles. Some of them were
large vegetarian animals, more than twelve feet in length; others were
carnivores with very powerful heads and teeth as formidable as those
of the tiger. Another branch of the same order lived on the sout