Origin of Species Variorum

Comparison with 1866

whatever the cause may be, confined ranges. Hence trees would be little likely to reach distant oceanic islands; and an herbaceous plant, though it might have no chance of successfully competing on a continent with many fully developed trees, when established on an island and having to compete with herbaceous plants alone, might readily gain an advantage over them by growing taller and overtopping them. If so, natural selection would often tend to add to the stature of herbaceous plants when growing on oceanic islands, to whatever order they belonged, and thus convert them first into bushes and ultimately into trees.

Absence of Batrachians and Terrestrial Mammals on Oceanic Islands .

With respect to the absence of whole orders on oceanic islands, Bory St. Vincent long ago remarked that Batrachians (frogs, toads, newts) have never been found on any of the many islands with which the great oceans are studded. I have taken pains to verify this assertion, and I have found it strictly true. I have, however, been assured that a frog exists on the mountains of the great island of New Zealand; but I suspect that this exception (if the information be correct) may be explained through glacial agency. ↑ This general absence of frogs, toads, and newts on so many oceanic islands cannot be accounted for by their physical conditions; indeed it seems that islands are peculiarly well fitted for these animals; for frogs have been introduced into Madeira, the Azores, and Mauritius, and have multiplied so as to become a nuisance. But as these animals and their spawn are known to be immediately killed by sea-water, on my view we can see that there would be great difficulty in their transportal across the sea, and therefore

what- ever the cause may be, confined ranges. Hence trees would he 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 by growing taller and taller and overtopping the other herbaceous plants. In this case, natural selection would .. tend to add to the stature of the plant, ... to whatever order it belonged, and thus convert it first into a bush and then into a tree.

Absence of Batrachians and Terrestrial Mammals on Oceania 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 strictly true, with the exception of New Zealand, of the Andaman Islands, and perhaps of the Salomon Islands. ↑ But I have already remarked that it is doubtful whether New Zealand ought to be classed as an oceanic island; and this is still more doubtful with respect to the Andaman and Salomon groups. This general absence of frogs, toads, and newts on so many oceanic islands cannot be accounted for by their physical conditions; indeed it seems that islands are peculiarly well fitted for these animals; for frogs have been introduced into Madeira, the Azores, and Mauritius, and have multiplied so as-to become a nuisance. But as these animals and their spawn are known to be immediately killed by sea-water, there would be great difficulty in their transportal across the sea, and therefore