PROBLEMS OF DISTRIBUTION AND THEIR SOLUTION. 141 



It is clear, therefore, that our glance at the world's geography in 

 relation to the distribution of life must go deeper into the nature of 

 things than do the common descriptions of the countries tenanted by 

 animal and plant races. Here, as in other departments of scientific 

 inquiry, we require to refer to a former state of things, and to glance 

 backwards in time for the true solution of the problems of life's 

 development over the globe. The naturalist of to-day thoroughly 

 endorses Mr. Wallace's statement, that " to the older school of 

 naturalists the native country of an animal was of little importance 



except in so far as climates differed A group of animals was 



said to inhabit the ' Indies ' ; and important differences of structure 

 were often overlooked from the idea that creatures equally adapted 

 to live in hot countries, and with certain general resemblances, would 



naturally be related to each other To the modern naturalist, 



on the other hand, the native country (or 'habitat,' as it is technically 

 termed) of an animal or a group of animals is a matter of the first 

 importance ; and as regards the general history of life upon the 

 globe, may be considered to be one of its essential characters." 



That certain divisions, or " regions," bounded by distinct lines of 

 demarcation, exist to represent the natural method of distribution of 

 animals or plants on the earth's surface, is a fact readily provable. 

 For example, one of the most remarkable results attained through 

 the investigation of the distribution of animals and plants, is the fact 

 that a line passing between the little islands of Bali and Lombok in 

 the eastern archipelago, and separating Borneo, Java, and the Philip- 

 pines from Celebes, New Guinea, and Australia (see fig. 13), serves 

 as a boundary between two regions exhibiting the greatest diversity 

 in their animal and plant life* On the Borneo side of this line 

 we have a rich collection of higher quadruped life man-like apes, 

 lemurs, monkeys, antelopes, tigers, rhinoceroses, and other forms 

 along with the babblers, hill-tits, bulbuls, crows, hornbills, pheasants, 

 and jungle-fowl among the birds. On the Australian side, not a 

 single higher quadruped (if we except a few bats, and rodents of 

 recent introduction) is native ; and the kangaroos and their neigh- 

 bours represent the fulness of quadruped life in the archipelago. 

 The special birds of the archipelago have for the most part disap- 

 peared. The bulbuls, pheasants, barbets, and vultures, find no place 

 in the Australian islands ; but in their place we find the curious 

 honeysuckers, the piping crows, the lyre-birds, the cockatoos, lories, 

 and parroquets, the brush-turkey and mound birds, emus and casso- 

 waries, and other characteristic forms. It is difficult to imagine a 

 change of fauna so complete as that which meets the eye of the 

 traveller as he passes across the narrow straits of Lombok to 

 enter the Australian region. Yet the divergence is of the most 

 characteristic nature, and depends upon the causes which lie at the 



