MAMMALS OF AUSTRALIA 175 



one stands out as a most memorable figure in the pageant of 

 science : Charles Darwin, whose name is associated for ever with 

 the great theories of evolution and natural selection. In the nine- 

 teenth chapter of his fascinating book, The Voyage of the ' Beagle, ' 

 Darwin describes his journeys in New South Wales, and gives some 

 fleeting impressions of man and beast as he found them there exist- 

 ing. Alfred Russell Wallace, whose name is as illustrious as that 

 of Darwin, has written wisely and well of Australian natural history, 

 and his passages on the marsupials and monotremes and other ancient 

 types that still survive in these regions are too well known to be 

 again quoted. 



It will be necessary, before proceeding with a description of 

 the fauna, to give some account of the geological history of the 

 Australian region, and the relationship of the marsupial forms to the 

 higher orders of mammals inhabiting other parts of the world. An 

 imaginary line known as Wallace's line passes between two small 

 Malayan islands, Bali and Lombok, and divides the Australian 

 region from the rest of the world. As every reader of The Malay 

 Archipelago will remember, the difference between the flora and 

 fauna of Bali and Lombok is greater than that which exists between 

 China and Peru. On the Asiatic side, Bali is linked with Java and 

 Sumatra, the habitat of the Rhinoceros, Elephant, Tiger and Tapir, 

 while Lombok's inclusion in the Australian zone is proved by the 

 presence of marsupial forms restricted to that region. It is believed 

 by geologists that aeons ago Australia was connected with South 

 America by means of an Antarctic continent; and there is also 

 evidence that South America, Africa and Australia were probably 

 united through a southern continent. It is fascinating to speculate 

 on these vanished "land-bridges," to recreate continents which, if 

 they ever had existence, disappeared in the sea long ere the advent 

 of man on this ancient planet. 



One of the most interesting evidences of the former land con- 

 nection between South America and Australia is found in the dis- 

 tribution of a species of fresh-water fish, the Mountain Trout, or 

 Minnow. This little fish is abundant in some Australian creeks and 

 streams ; the boys of the bush catch it on sunny half-holidays, little 

 knowing its wonderful history. The Mountain Trout is also found 

 in the lakes and rivers of Patagonia, and it has been captured in 

 some of the islands which lie midway between the two Continents. 

 Then, at Santa Cruz, on the coast of South America, fossil remains 



