438 THE PAPUAN ISLANDS. [chap, xxxix. 



These remarks have an important bearing on the problem 

 of dividing the surface of the earth into great regions, dis- 

 tinguished by the radical difference of their natural pro- 

 ductions. Such difference we now know to be the direct 

 result of long-continued separation by more or less im- 

 passable barriers ; and as wide oceans and great contrasts 

 of temperature are the most complete barriers to the 

 dispersal of all terrestrial forms of life, the primary 

 divisions of the earth should in the main serve for all 

 terrestrial organisms. However various may be the efiects 

 of climate, however unequal the means of distribution, 

 these will never altogether obliterate the radical effects of 

 long- continued isolation ; and it is my firm conviction, that 

 when the botany and the entomology of New Guinea and 

 the surrounding islands become as well known as are 

 their mammals and birds, these departments of nature 

 will also plainly indicate the radical distinctions of the 

 ludo-Malayan and Austro-Malayan regions of the great 

 Malay Archipelago. 



