350 ABSENCE OF TERRESTRIAL MAMMALS [Chap. XIII. 



the soldered wing-covers of many insular beetles. Again, islands 

 often possess trees or bushes belonging to orders which elsewhere 

 include only herbaceous species ; now trees, as Alph. de Candolle 

 has shown, generally have, whatever the cause may be, confined 

 ranges. Hence trees would be little likely to reach distant oceanic 

 islands ; and an herbaceous plant, which had no chance of success- 

 fully competing with the many fully developed trees growing on 

 a continent, might, when established on an island, gain an advan- 

 tage over other herbaceous plants by growing taller and taller and 

 overtopping them. In this case, natural selection would tend to 

 add to the stature of the plant, to whatever order it belonged, and 

 thus first convert it into a bush and then into a tree. 



Absence of Batrachians and Terrestrial Mammals on Oceanic 

 Islands. 



With respect to the absence of whole orders of animals on oceanic 

 islands, Bory St. Vincent long ago remarked that Batrachians 

 (frogs, toads, newts) are never found on any of the many islands 

 with which the great oceans are studded. I have taken pains to 

 verify this assertion, and have found it true, with the exception 

 of Xew Zealand, New Caledonia, the Andaman Islands, and per- 

 haps the Salomon Islands and the Seychelles. But I have already 

 remarked that it is doubtful whether New Zealand and New Cale- 

 donia ought to be classed as oceanic islands ; and this is still more 

 doubtful with respect to the Andaman and Salomon groups and 

 the 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 introduced into Ma- 

 deira, the Azores, and Mauritius, and have multiplied so as to 

 become a nuisance. But as these animals and their spawn are im- 

 mediately killed (with the exception, as far as known, of one Indian 

 species) by sea-water, there would be great difficulty in their trans- 

 portal across the sea, and therefore we can see why they do not 

 exist on strictly oceanic islands. But why, on the theory of crea- 

 tion, 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 



