INHABITANTS OF OOEANIO ISLANDS. 413 



certain islands not tenanted by a single mammal, some of 

 the endemic plants have beautifully hooked seeds; yet few 

 relations are more manifest than that hooks serve for the 

 transportal of seeds in the wool or fur of quadrupeds. 

 But a hooked seed might bo carried to an island by other 

 means; and the plant then becoming modified would form 

 an endemic species, still retaining its hooks, which would 

 form a useless appendage, like the shrivelled wings under 

 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 Oandolle 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 successfully 

 competing with the many fully developed trees growing on 

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

 advantage 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 BATEACHIANS AND TEEEESTKIAL 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 New Zealand, 

 ■New Cfiledonia, the Andaman Islands, and perhaps the 

 Solomon Islands and the Seychelles. But I have already 

 remarked that it is doubtful whether New Zealand and 

 New Caledonia ought to be classed as oceanic islands; and 

 this is still more doubtful with respect to the Andaman and 

 Solomon groups and the Seychelles. This general absence 

 of frogs, toads and newts on so many true ocea.nic islands 

 can not be accounted for by their physical conditions: in- 

 deed it seems that islands are peculiarly fitted for these 

 animals; for frogs have been introduced into Madeira, the 



