V A GLIMPSE INTO THE PAST 131 



groups of Honey-eaters, Cockatoos, and Mound- 

 birds being entirely absent. On crossing over 

 Wallace's line, even across the fifteen-mile straits 

 between Bali and Lombok, we are at once in 

 a different world, the Australian world of Euca- 

 lypts. Cockatoos, Honey-eaters and Marsupial 

 Mammals. The small amount of intermixture 

 that has taken place in these and neighbouring 

 islands concerns species which have evidently 

 only recently migrated across the line, as is 

 shown by the fact that very few of them have 

 yet had time to become specifically different in 

 the two regions. 



It is plain, therefore, that a direct land con- 

 nexion of Australia and New Guinea with Asia, 

 if it ever existed, belonged to a very ancient epoch 

 when the natural products of the two countries 

 were totally unlike those of the present day. The 

 southern islands of the archipelago, stretching from 

 Java towards New Guinea, are volcanic in origin, 

 and many of the volcanoes are still active, thus 

 very likely representing a fairly modern upheaval, 

 so that the connexion of the Australian Hegion 

 with Asia is probably closer now than it has been 

 for a long time in the past. 



Whence, then, did Australia receive its living 

 inhabitants, or with the inhabitants of what part 

 of the world, and at what epoch, were they 

 connected and in common derived ? To discuss 

 this question it is necessary first of all to note 

 that the Australian Region itself falls naturally 



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