in the distribution of animals.  Subsequent writers have considerably extended Huxley’s conception of the similarities to be found among the more southern land areas.  They have pointed out that the most striking idea of the distribution of land and water on the surface of the globe is to be got by considering the globe alternately from one pole and from the other.  In the south, a clump of ice-bound land, well within the Antarctic Circle, surrounds the pole.  All else is a wide domain of ocean broken only where tapering and isolated tongues of land, South America, the Cape, Australia, lean down from the great land masses of the north.  On the other hand, all the great land masses expand in the Northern Hemisphere, and shoulder one another round the North Pole.  America is separated from Asia only by the shallowest and narrowest of straits; an elevation of a few fathoms would unite Greenland with Europe.  Science points definitely to some part of the great northern land area as the centre of life 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.