fe for at
least the larger terrestrial forms of life. We know that these arose
successively, primitive birds like the ostriches being older than
higher forms like the parrots and singing birds; the pouched
marsupials preceding the antelopes and the lion; the lemurs coming
before the man-like apes. Each wave of life spread over the whole area
producing after its kind; then, pressing round the northern land area,
it met a thousand different conditions of environment, different
foods, enemies, and climates, and broke up into different genera and
species. But there was never a wave of life that was not followed by
another wave. In the struggle for existence between the newer and the
older forms, the older forms were gradually driven southwards towards
the diverging fringes of the land masses. The vanquished left behind
them on the field of battle only their bones, to become fossils.
Sometimes succeeding waves swept along to the extreme limits of the
land, and many early types were utterly destroyed. But others found
sanctuary in the ends of the South, and such survivors of older and
earlier types of life cause a similarity between the southern lands
that Huxley called Notogaea, although the extent of his region must be
increased.

Recently, however, there has been a recurrence to Huxley's suggested
union of South America and Australia, based on new evidence of a
direct kind, quite different from that which had just been given.
Various groups of naturalists have stated that there are similarities
between the invertebrate inhabitants of Australia and of South America
of a kind which makes the existence of a direct land connection in the
Southern Hemisphere extremely probable. Moreover, Ameghino has
recently described some marsupial fossils from South America which, he
states, belong to the Australian group of Dasyuridae, and Oldfield
Thomas has described a new mammal from South America which is unlike
the opossums of America and like the diprotodonts of Australia. So
that, while the general opinion has been against Huxley's division,
Notogaea, in the strict meaning which he gave to it, there has recently
been an opinion growing in its favour.

Huxley also made minor alterations in Mr. Sclater's scheme by forming
an additional circumpolar region for the Northern Hemisphere, and by
elevating New Zealand into a separate region, distinct from Australia.
On these points there is a balance of opinion against his views.

Before