Physical Geography. 27 



In fact, the 100-fathom line round New Guinea marks out ac- 

 curately the range of the true paradise birds. 



It is further to be noted — and this is a very interesting 

 point in connection with theories of the dependence of special 

 forms of life on external conditions — that this division of the 

 Archipelago into two regions characterized by a striking di- 

 versity in their natural productions, does not in any way cor- 

 respond to the main physical or climatal divisions of the sur- 

 face. The great volcanic chain runs through both parts, and 

 appears to produce no effect in assimilating their productions. 

 Borneo closely resembles New Guinea not only in its vast 

 size and Its freedom from volcanoes, but in its variety of geo- 

 logical structure, its uniformity of climate, and the general 

 aspect of the forest vegetation that clothes its surface. The 

 Moluccas are the counterpart of the Philippines in their vol- 

 canic structui-e, their extreme fertility, their luxuriant forests, 

 and their frequent earthquakes ; and Bali with the east end 

 of Java has a climate almost as dry and a soil almost as arid 

 as that of Timor. Yet between these corresponding groups 

 of islands, constructed as it were after the same pattern, sub- 

 jected to the same climate, and bathed by the same oceans, 

 there exists the greatest possible contrast when we compare 

 their animal productions. Nowhere does the ancient doctrine 

 — that differences or similarities in the various forms of life 

 that inhabit different countries are due to corresponding phys- 

 ical differences or similarities in the countries themselves — 

 meet with so direct and palpable a contradiction. Borneo and 

 New Guinea, as alike physically as two distinct countries can 

 be, are zoologically wide as the poles asunder; while Aus- 

 tralia, with its dry winds, its open plains, its stony deserts, and 

 its temperate climate, yet produces birds and quadrupeds 

 which are closely related to those inhabiting the hot, damp, 

 luxuriant forests which everywhere clothe the plains and 

 mountains of New Guinea. 



In order to illustrate more clearly the means by which I 

 suppose this great contrast has been brought about, let us 

 consider what would occur if two strongly-contrasted divis- 

 ions of the earth were, by natural means, brought into prox- 

 imity. No two parts of the world differ so radically in their 

 productions as Asia and Australia, but the difference between 



