20 EVOLUTION 



the original centre, and of transformation 

 into new species in relation to the new con- 

 ditions encountered. Some of the particular 

 case leap to the eye, but they are unmeaning 

 conundrums without the evolutionist clue. 

 Darwin has, in fact, brought us more nearly 

 back to the Noah's ark of our childhood than 

 we commonly realize; for do not all these 

 stories of thrushes, lizards and what not 

 quaintly recall the origin of human races from 

 the dispersion of Shem, Ham and Japheth.f^ 



In Mesozoic times, when there were no 

 Mammals higher than Marsupials, Australia 

 was separated off from the Asiatic continent. 

 Therefore it is that there are no higher 

 Mammals in Australia, except the somewhat 

 mysterious dingo, the bats, which find the sea 

 no barrier, and the rabbits, for which man 

 is responsible. 



A final argument is furnished by the con- 

 trast in the fauna and flora of oceanic and of 

 continental islands. The former, being usu- 

 ally of volcanic origin, have always a very 

 distinctive fauna and flora, which Wallace 

 has explained as being due to the fortuitous 

 contributions borne from diverse quarters by 

 currents, winds and birds. Other islands, 

 which are isolated pieces of continents, have 

 a fauna and flora like that of the nearest part 

 of the mainland. 



