DOI link for Geographical Distribution
Geographical Distribution book
This chapter talks about distribution of freshwater productions, on the inhabitants of oceanic islands, absence of Batrachians and of terrestrial mammals, on the relation of the inhabitants of islands to those of the nearest mainland, on colonization from the nearest source with subsequent modification. Some species of freshwater shells have a very wide range, and allied species, which, on author theory, are descended from a common parent, and must have proceeded from a single source, prevail throughout the world. With respect to plants, it has long been known what enormous ranges many freshwater and even marsh species have, both over continents and to the most remote oceanic islands. The species of all kinds which inhabit oceanic islands are few in number compared with those on equal continental areas: Alph. de Candolle admits this for plants, and Wollaston for insects.