CHAPTER V

THE POWERS OF DISPERSAL OF ANIMALS AND PLANTS

Statement of the General Question of Dispersal--The Ocean as a Barrier to the Dispersal of Mammals--The Dispersal of Birds--The Dispersal of Reptiles--The Dispersal of Insects--The Dispersal of Land Mollusca--Great Antiquity of Land-shells--Causes Favouring the Abundance of Land-shells--The Dispersal of Plants--Special Adaptability of Seeds for Dispersal--Birds as Agents in the Dispersal of Seeds--Ocean Currents as Agents in Plant Dispersal--Dispersal along Mountain Chains--Antiquity of Plants as Effecting their Distribution

_Pages_ 72-82