436 ORIGIN OF SPECIES 



Seychelles. This general absence of frogs, toads, and newts 

 on so many true oceanic islands cannot be accounted for by 

 their physical conditions : indeed it seems that islands are 

 peculiarly fitted for these animals ; for frogs have been intro- 

 duced into Madeira, the Azores, and Mauritius, and have 

 multiplied so as to become a nuisance. But as these animals 

 and their spavin are immediately killed (with the exception, 

 as far as known, of one Indian species) by sea-water, there 

 would be great difficulty in their transportal across the sea, 

 and therefore we can see why they do not exist on strictly 

 oceanic islands. But why, on the theory of creation, they 

 should not have been created there, it would be very difficult 

 to explain. 



Mammals offer another and similar case. I have carefully 

 searched the oldest voyages, and have not found a single 

 instance, free from doubt, of a terrestrial mammal (excluding 

 domesticated animals kept by the natives) inhabiting an island 

 situated above 300 miles from a continent or great continental 

 island; and many islands situated at a much less distance are 

 equally barren. The Falkland Islands, which are inhabited 

 by a wolf-like fox, come nearest to an exception ; but this 

 group cannot be considered as oceanic, as it lies on a bank 

 in connection with the mainland at the distance of about 280 

 miles ; moreover, icebergs formerly brought boulders to its 

 western shores, and they may have formerly transported 

 foxes, as now frequently happens in the arctic regions. Yet 

 it cannot be said that small islands will not support at least 

 small mammals, for they occur in many parts of the world 

 on very small islands, when lying close to a continent ; and 

 hardly an island can be named on which our smaller quadru- 

 peds have not become naturalised and greatly multiplied. It 

 cannot be said, on the ordinary view of creation, that there 

 has not been time for the creation of mammals ; many vol- | 



canic islands are sufficiently ancient, as shown by the stu- 

 pendous degradation which they have suffered, and by their 

 tertiary strata : there has also been time for the production 

 of endemic species belonging to other classes ; and on conti- 

 nents it is known that new species of mammals appear and 

 disappear at a quicker rate than other and lower animals. 

 Although terrestrial mammals do not occur on oceanic 



