Chapter III: Preface: To the First Edition

The present volume is the result of four years' additional thought and research on the lines laid down in my _Geographical Distribution of Animals_, and may be considered as a popular supplement to and completion of that work.

It is, however, at the same time a complete work in itself: and, from the mode of treatment adopted, it will, I hope, be well calculated to bring before the intelligent reader the wide scope and varied interest of this branch of natural history. Although some of the earlier chapters deal with the same questions as my former volumes, they are here treated from a different point of view; and as the discussion of them is more elementary and at the same time tolerably full, it is hoped that they will prove both instructive and interesting. The plan of my larger work required that _genera_ only should be taken account of; in the present volume I often discuss the distribution of _species_, and this will help to render the work more intelligible to the unscientific reader.

The full statement of the scope and object of the present essay given in the "Introductory" chapter, together with the "Summary" of the whole work and the general view of the more important arguments given in the "Conclusion," render it unnecessary for me to offer any further remarks on these points. I may, however, state {x} generally that, so far as I am able to judge, a real advance has here been made in the mode of treating problems in Geographical Distribution, owing to the firm establishment of a number of preliminary doctrines or "principles," which in many cases lead to a far simpler and yet more complete solution of such problems than have been hitherto possible. The most important of these doctrines are those which establish and define--(1) The former wide extension of all groups now discontinuous, as being a necessary result of "evolution"; (2) The permanence of the great features of the distribution of land and water on the earth's surface; and, (3) The nature and frequency of climatal changes throughout geological time.

I have now only to thank the many friends and correspondents who have given me information or advice. Besides those whose assistance is acknowledged in the body of the work, I am especially indebted to four gentlemen who have been kind enough to read over the proofs of chapters dealing with questions on which they have special knowledge, giving me the benefit of valuable emendations and suggestions. Mr. Edward R. Alston has looked over those parts of the earlier chapters which relate to the mammals of Europe and the North Temperate zone; Mr. S. B. J. Skertchley, of the Geological Survey, has read the chapters which discuss the glacial epoch and other geological questions; Professor A. Newton has looked over the passages referring to the birds of the Madagascar group; while Sir Joseph D. Hooker has given me the invaluable benefit of his remarks on my two chapters dealing with the New Zealand flora.

CROYDON, _August, 1880_.

* * * * *

{xi}

CONTENTS

PART I

THE DISPERSAL OF ORGANISMS; ITS PHENOMENA, LAWS, AND CAUSES

CHAPTER I

INTRODUCTORY

Remarkable Contrasts in the Distribution of Animals--Britain and Japan--Australia and New Zealand--Bali and Lombok--Florida and Bahama Islands--Brazil and Africa--Borneo, Madagascar, and Celebes--Problems in Distribution to be found in every Country--Can be Solved only by the Combination of many distinct lines of inquiry, Biological and Physical--Islands offer the best Subjects for the Study of Distribution--Outline of the Subjects to be discussed in the Present Volume.

_Pages_ 3-11

CHAPTER II

THE ELEMENTARY FACTS OF DISTRIBUTION.

Importance of Locality as an Essential Character of Species--Areas of Distribution--Extent and Limitations of Specific Areas--Specific Range of Birds--Generic Areas--Separate and Overlapping Areas--The Species of Tits as illustrating Areas of Distribution--The Distribution of the Species of Jays--Discontinuous Generic Areas--Peculiarities of Generic and Family Distribution--General Features of Overlapping and Discontinuous Areas--Restricted 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