310 THE INFLUENCE OF INANIMATE SXmEOUNDIHGS. 



Certainly he includes in the Indian the Siinia islands, which 

 Wallace, who first attempted to explain this contrast, placed in 

 the Australian region. The limit-line, which, according, to 

 "Wallace, sharply divides these two regions, runs between the 

 two islands of Bali and Lombok, close as these two lie to each 

 other. He reckons the fauna of Bali with that of Java, while 

 that of Lombok is said to be completely ditferent, and to belong 

 to the Moluccas. From thence the limit between these two 

 provinces runs somewhat to the north-east, between Borneo, 

 which still belongs to the Indian, and Celebes ; it then turns 

 abruptly to the east ; thus all the Philippine islands are thrown 

 into the Indian region, while a few of the smaller groups, form- 

 ing a connection between Mindanao and Gilolo and New 

 Guinea, lie south of this limit-line and are thus included in the 

 great Avistralian region. The line thus laid down has been 

 designated as Wallace's line, in honour of its founder. 



It cannot be disputed that this line seems, in fact, a very 

 natural one, if only the birds and mammalia are taken into con- 

 sideration and the insects not brought into the comparison. In 

 the Australian region the Marsupials, birds of Paradise, Mono- 

 tremata, lyre-birds, cockatoos, cassowaries, and the very peculiar 

 TrichoglossidsB ; in the Indian region, on the other hand, the 

 apes, lemurs and Hying squirrels, Gahopiihecvs, and many other 

 Mammalia which are absent from the Australian region. Among 

 birds, the Argus pheasant, the peacock and Euplocamvs, the 

 various pigeons, and of parrots the Loriculus and Palaiornis, 

 with many others, never occur in the Australian region. 

 We must not, however, leave out of the question the fact that 

 many of these forms, or of others equally characteristic, not 

 rarely pass across into the neighbouring region, where the two 

 come into contact. Wallace himself points this out. But the 

 contrast is much less sharply defined in the Reptiles, Amphibiia, 

 and even the Insects ; thus Pascoe, who has the most perfect 

 knowledge of the Coleoptera of the eastern hemisphere, says 

 that, as regards its beetles. New Guinea most positively belongs 

 to the Indian region, and that they are quite clearly distinct 

 from the Coleoptera of New Holland. Hence the contrast indi- 

 cated is not absolute throughout, and Wallace himself, in hia 



