ble of the higher canine traits, and with a suspicious, ferocious, glaring eye, that betrays at once his uncivilizable 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 civilization of Europe and the civilization of Mexico or Peru, The Mexicans, when Cortes 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 the mound-builders in Britain. Even so, though Australia is still zoölogically 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 birdlike 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 the higher types which have since been evolved in Europe and Asia. Even in Australia itself the ornithorhynchus and echidna have had to put up perforce with the lower places in the hierarchy of Nature, The first is a burrowing and aquatic creature, specialized in a thousand minute ways for his amphibious life and queer subterranean habits; the second is a spiny, hedgehog-like nocturnal prowler, who buries himself in the earth during the day, and lives by night on insects which he licks up greedily with his long, ribbon-like tongue. Apart from the specializations brought about by their necessary adaptation to a particular niche in the economy of life, these two quaint and very ancient animals probably preserve for us in their general structure the features of an extremely
