The typical Australian animals disappear as we travel away through the islands to the north, and the boundary line between Australia and Asia is usually drawn through the strait between Bali and Lombok, and then on between Celebes and Borneo; though it is much disputed whether Celebes belongs to the one region or the other. The division is only a narrow water strait, and we can understand that Asiatic birds would have no difficulty in crossing. On the other hand, as there is no great land mass to the south, there are no crowds of seasonal migrants from cooler regions, such as we find in the warmer countries of the northern hemisphere; so that the existing Australian birds are for the most part allied to the bright-coloured inhabitants of the tropics to the north. Some are peculiar to the region, such 18 as the lyre birds with their wonderful tails, the emu, and the 19 brush birds which bury their eggs in a mound of earth, leaving them to be hatched by the heat of the sun. Other birds, as the honey-eaters, though common in Australia, are found also in the neighbouring islands of the Pacific. Unfortunately, not content 20 with the flowers of the gum trees, these birds now attack the fruit in the orchards and are becoming a nuisance in some districts. Finally we have the _kukuburra_ or laughing-jackass, 21 one of the most popular and best known of all Australian birds. It belongs to the kingfisher tribe and is said to be a great destroyer of small snakes. Nor must we forget the black swan, one 22 of the most striking and beautiful of all, and still to be found in large numbers in the lakes of Gippsland and in West Australia. Then we have lizards, snakes, and strange fish of all kinds, some peculiar to Australia, others, like the animals, allied to species found in Asia or South America. All the evidence afforded by the animal life of the continent points to a very remote connexion with the other continents, followed by a very long period of isolation during which the families of animals developed wide differences among themselves, together with special peculiarities suited to the conditions in which they lived.