OCEANIC ISLANDS. 



309 



Azores are situated in an especially stormy zone, and 

 it is an observed fact tliat after every severe gale of 

 wind some new bird or insect is seen on the islands. 

 The Galapagos, on the contrary, are in a very calm 

 sea where violent storms are almost unknown, and 

 thus new birds from the mainland very rarely visit these 

 islands. Madeira is less stormy than the Azores, but 

 its comparative nearness makes up for this difierence in 

 the case of birds. In insects, however, the species of 

 Madeira are much more peculiar (and more numerous) 

 than those of the more distant Azores ; while those of 

 the Galapagos are few, but all peculiar, and belonging 

 to groups many of which are widely spread over the 

 globe. All these facts are entirely in accordance with 

 the view that oceanic islands have been peopled from 

 the nearest continents by various accidental causes ; 

 while they are entirely opposed to the theory that such 

 islands are remnants of old continents and have 

 preserved some portion of their inhabitants. 



It is a curious fact, that land reptiles, such as snakes 

 and lizards, are found in many islands where there are 

 no mammalia or frogs ; and we therefore conclude that 

 there must be some means by which their ova can be 

 safely carried across great widths of sea. A single 

 peculiar frog inhabits New Zealand, and some species are 

 found in the Pacific islands as far eastward as the Fijis, 

 but they are absent from all other oceanic islands. 

 Snakes also extend to the Fijis, and there are two species 

 in the Galapagos, but none in the other oceanic islands. 

 Lizards, however, are found in Mauritius and Bourbon ; 

 in New Zealand ; in all the Pacific islands, and in the 

 Galapagos. It is clear then that next to Mammals, 



