of continents.  For the Australian black-fellow must have got there a very long time ago indeed; he belongs to an extremely ancient human type, and strikingly recalls in his jaws and skull the Neanderthal savage and other early prehistoric races; while the woolly-headed Tasmanian, a member of a totally distinct human family, and perhaps the very lowest sample of humanity that has survived to modern times, must have crossed over to Tasmania even earlier still, his brethren on the mainland having no doubt been exterminated later on when the stone-age Australian black-fellows first got cast ashore upon the continent inhabited by the yet more barbaric and helpless negrito race.  As for the dingo, or Australian wild dog, only half domesticated by the savage natives, he represents a low ancestral dog type, half wolf and half jackal, incapable of the higher canine traits, and with a suspicious, ferocious, glaring eye that betrays at once his uncivilisable tendencies.

Omitting these later importations, however—­the modern plants, birds, and human beings—­it may be fairly said that Australia is still in its secondary stage, while the rest of the world has reached the tertiary and quaternary periods.  Here again, however, a deduction must be made, in order to attain the necessary accuracy.  Even in Australia the world never stands still.  Though the Australian animals are still at bottom the European and Asiatic animals of the secondary age, they are those animals with a difference.  They have undergone an evolution of their own.  It has not been the evolution of the great continents; but it has been evolution all the same; slower, more local, narrower, more restricted, yet evolution in the truest sense.  One might compare the difference to the difference between the civilisation of Europe and the civilisation of Mexico or Peru.  The Mexicans, when Cortez blotted out their indigenous culture, were still, to be sure, in their stone age; but it was a very different stone age from that of the cave-dwellers or mound builders in Britain.  Even so, though Australia is still zoologically in the secondary period, it is a secondary period a good deal altered and adapted in detail to meet the wants of special situations.

The oldest types of animals in Australia are the ornithorhynchus and the echidna, the ‘beast with a bill,’ and the ‘porcupine ant-eater’ of popular natural history.  These curious creatures, genuine living fossils, occupy in some respects an intermediate place between the mammals on the one hand and the birds and lizards on the other.  The echidna has no teeth, and a very bird-like skull and body; the ornithorhynchus has a bill like a duck’s, webbed feet, and a great many quaint anatomical peculiarities which closely ally it to the birds and reptiles.  Both, in fact, are early arrested stages in the development of mammals from the old common vertebrate ancestor; and they could only have struggled on to our own day in a continent free from the severe competition of