354 ON THE ORIGIN OF SPECIES 



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

 connected with the mainland ; moreover, icebergs for- 

 merly brought boulders to its western shores, and they 

 may have formerly transported foxes, as so frequently 

 now happens in the arctic regions. Yet it cannot be 

 said that small islands will not support small mammals, 

 for they occur in many parts of the world on very 

 small islands, if close to a continent ; and hardly an [ 

 island can be named on which our smaller quadrupeds: 

 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 mam- 

 mals ; many volcanic islands are sufficiently ancient, 

 as shown by the stupendous 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 continents it is 

 thought that mammals appear and disappear at a, 

 quicker rate than other and lower animals. Though! 

 terrestrial mammals do not occur on oceanic islandsJ 

 aerial mammals do occur on almost every island. Newi 

 Zealand possesses two bats found nowhere else in the 

 world : Norfolk Island, the Viti Archipelago, the Bonin 

 Islands, the Caroline and Marianne Archipelagoes, and 

 Mauritius, all possess their peculiar bats. Why, it 

 may be asked, has the supposed creative force pro- 

 duced bats and no other mammals on remote islands S 

 On my view this question can easily be answered ; for 

 no terrestrial mammal can be transported across a wide 

 space of sea, but bats can fly across. Bats have been 

 seen wandering by day far over the Atlantic Ocean ^ 

 and two North American species either regularly or 

 occasionally visit Bermuda, at the distance of 600 miles 

 from the mainland. I hear from Mr. Tomes, who has 

 specially studied this family, that many of the same 

 species have enormous ranges, and are found on conti- 

 nents and on far distant islands. Hence we have only 

 to suppose that such wandering species have been modi- 

 fied through natural selection in their new homes in re- 

 lation to their new position, and we can understand the 



