xii 



CONTEXTS 



CHAPTER III 



CLASSIFICATION OF THE FACTS OF DISTRIBUTION. — ZOOLOGICAL REGIONS 



The Geographical Divisions of tlie 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 

 Palsearctic Region — Characteristic Features of the Palsearctic 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 lY 



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 — Con- 

 cluding 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 Abundan-ce 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 Etfecting 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 



