394 GEOGRAPHICAL DISTRIBUTION. Chap. XII. 



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 islands, 

 aerial mammals do occur on almost every island. New 

 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 produced 

 bats and no other mammals on remote islands? 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- 



