GEOGRAPHICAL DISTRIBUTION OF ANIMALS 



mals, and the fact that the absence of such animals is due to 

 their inabiHty to reach the islands, except by human aid, is 

 shown by the oft-repeated results of artificial introduction. 

 Rats, mice, rabbits, swine, goats, cattle, and horses, when 

 allowed to run wild on such islands, have thrived and multi- 

 plied exceedingly, showing that no unfavourable factor in 

 the environment prevented their presence. 



The fact that the oceanic islands really have been supplied 

 with their plants and animals by the more or less accidental 

 agency of the sea and the winds is indicated by a remarkable 

 instance, of which we have the whole history, for it took 

 place within recent years. In the Straits of Sunda, between 

 Java and Sumatra, there is a volcanic island called Krakatau, 

 which, in the summer of 1883 was the scene of a series of the 

 most tremendous volcanic explosions that have occurred 

 within historic time. In consequence of this terrific out- 

 burst, most of the island was destroyed and such parts of it 

 as remained above water were so deeply buried by volcanic 

 ash that all animal and vegetable . life was completely 

 destroyed; apparently not a living thing was left. Yet in 

 twenty years, or less, the desolate island was restocked by 

 the winds and ocean currents. The late Professor Selenka, 

 of Munich, visited Krakatau some years after the catastrophe, 

 and wrote of it: 



Under the shade of a Casudvina, among cocoanut palms and 

 thickets as high as a man's hea4, I found, to my astonishment, an 

 active animal life of spiders, flies, bugs, beetles, and butterflies ; even 

 lizards half a yard in length animated the peaceful picture. Ail 

 these plants and animals were brought hither by wind and water 

 from Java and Sumatra, replacing the vanished world in the course 

 of a few years. 



If the living things on oceanic islands, animal and vege- 

 table, were not created especially for them, they must have 



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