OCEANIC ISLANDS. 307 



subject by pointing out that the great Malay Archipelago 

 may be divided in two portions, all the islands in the 

 western half being united to each other and to the 

 continent of Asia by a very shallow sea, and all having 

 very similar productions, while many large animals, such 

 as the elephant, rhinoceros, wild cattle, and tigers, range 

 over most of them. We then come to a profoundly 

 deep sea, and the islands of the eastern half of the archi- 

 pelago are either surrounded by a deep sea or are con- 

 nected by a shallow sea to Australia; and in this half 

 the productions resemble those of Australia, marsupials 

 being found in all the islands while the large quadrupeds 

 of Asia are almost wholly unknown. 



Theory of Oceanic Islands. In 1859 the Origin of 

 S$>ecies was published, and in the thirteenth chapter 

 of this celebrated work Mr. Darwin put forth his views 

 on oceanic islands or such as are situated far away from 

 any continent and are surrounded by deep oceans. It 

 had been up to this time believed that in most cases 

 these islands were fragments of ancient continents ; as 

 an example of which we may refer to the Azores, Madeira, 

 and the other Atlantic islands, which were thought to 

 support the notion of an Atlantic or western extension of 

 the European continent. In order to ascertain what was 

 the condition of these islands when first discovered, Mr. 

 Darwin searched through all the oldest voyages, and 

 found that in none of them was a single native mammal 

 known to exist, while in almost all of them frogs and 

 toads were also absent. All the Atlantic isles from the 

 Azores to St. Helena ; Mauritius, Bourbon, and the 

 other isles of the Indian Ocean ; and the Pacific islands, 

 east of the Fijis, as far as the Galapagos and Juan 



X 2 



