d Areas of Families--The Distribution of Orders

_Pages_ 12-30

{xii}

CHAPTER III

CLASSIFICATION OF THE FACTS OF DISTRIBUTION.--ZOOLOGICAL REGIONS

The Geographical Divisions of the Globe do not Correspond to Zoological
Divisions--The Range of British Mammals as Indicating a Zoological
Region--Range of East Asian and North African Mammals--The Range of British
Birds--Range of East Asian Birds--The Limits of the Palaearctic
Region--Characteristic Features of the Palaearctic Region--Definition and
Characteristic Groups of the Ethiopian Region--Of the Oriental Region--Of
the Australian Region--Of the Nearctic Region--Of the Neotropical
Region--Comparison of Zoological Regions with the Geographical Divisions of
the Globe

_Pages_ 31-54

CHAPTER IV

EVOLUTION AS THE KEY TO DISTRIBUTION

Importance of the Doctrine of Evolution--The Origin of New
Species--Variation in Animals--The amount of Variation in North American
Birds--How New Species Arise from a Variable Species--Definition and Origin
of Genera--Cause of the Extinction of Species--The Rise and Decay of
Species and Genera--Discontinuous Specific Areas, why Rare--Discontinuity
of the Area of Parus Palustris--Discontinuity of Emberiza Schoeniclus--The
European and Japanese Jays--Supposed examples of Discontinuity among North
American Birds--Distribution and Antiquity of Families--Discontinuity a
Proof of Antiquity--Concluding remarks

_Pages_ 55-71

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

CHAPTER VI

GEOGRAPHICAL AND GEOLOGICAL CHANGES: THE PERMANENCE OF CONTINENTS

Changes of Land and Sea, their Nature and Extent--Shore-Deposits and
Stratified Rocks--The Movements of Continents--Supposed Oceanic {xiii}
Formations; the Origin of Chalk--Fresh-water and Shore-deposits as Proving
the Permanence of Continents--Oceanic Islands as Indications of the
Permanence of Continents and Oceans--General Stab