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--Restricte