Somehow, on this theory of a single origin, he made his way to every quarter of the globe; and when he got there, though needing time, perhaps, to acquire the local colour, managed in the end to be at home.

It looks as if both race and a dash of culture had a good deal to do with his exploitation of geographical opportunity.

How did the Australians and their Negrito forerunners invade their Austral world, at some period which, we cannot but suspect, was immensely remote in time?
Certain at least it is that they crossed a formidable barrier.

What is known as Wallace's line corresponds with the deep channel running between the islands of Bali and Lombok and continuing northwards to the west of Celebes.

On the eastern side the fauna are non-Asiatic.