362 ON THE ORIGIN OF SPECIES 



sure can see that their eggs or larvae, perhaps attached 

 to seaweed or floating timber, or to the feet of wading - 

 birds, might be transported far more easily than land- 



->lls, across three or four hundred miles of open sea. 

 The different orders of insects in Madeira apparently 

 present analogous facts. 



Oceanic islands are sometimes deficient in certain 

 classes, and their places are apparently occupied by 

 the other inhabitants ; in the Galapagos Islands reptiles, 

 and in New Zealand gigantic wingless birds, take the 

 place of mammals. In the plants of the Galapagos 

 Islands, Dr. Hooker has shown that the proportional 

 numbers of the different orders are very different from 

 what they are elsewhere. Such cases are generally 

 accounted for by the physical conditions of the islands ; 

 but this explanation seems to me not a little doubtful. 

 Facility of immigration, I believe, has been at least as 

 important as the nature of the conditions. 



Many remarkable little facts could be given with 

 respect to the inhabitants of remote islands. For 

 instance, in certain islands not tenanted by mammals, 

 some of the endemic plants have beautifully hooked 

 seeds ; yet few relations are more striking than the 

 adaptation of hooked seeds for transportal by the wool 

 and fur of quadrupeds. This case presents no difficulty 

 on my view, for a hooked seed might be transported to 

 an island by some other means ; and the plant then 

 becoming slightly modified, but still retaining its hooked 

 seeds, would form an endemic species, having as useless 

 an appendage as any rudimentary organ, — for instance, 

 as the shrivelled wings under the soldered elytra 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 herb- 

 aceous plant, though it would have no chance of 

 successfully competing in stature with a fully de- 

 veloped tree, when established on an island and having 



