late to introduce Wallace's name in 1876, the year of the
publication of his standard work. ("The Geographical Distribution of
Animals", 2 vols. London, 1876.) We cannot do better than quote the
author's own words, expressing the hope that his "book should bear a
similar relation to the eleventh and twelfth chapters of the "Origin of
Species" as Darwin's "Animals and Plants under Domestication" does to
the first chapter of that work," and to add that he has amply succeeded.
Pleading for a few primary centres he accepts Sclater's six regions and
does not follow Huxley's courageous changes which Sclater himself had
accepted in 1874. Holding the view of the permanence of the oceans he
accounts for the colonisation of outlying islands by further elaborating
the views of Lyell and Darwin, especially in his fascinating "Island
Life", with remarkable chapters on the Ice Age, Climate and Time and
other fundamental factors. His method of arriving at the degree
of relationship of the faunas of the various regions is eminently
statistical. Long lists of genera determine by their numbers the
affinity and hence the source of colonisation. In order to make sure
of his material he performed the laborious task of evolving a new
classification of the host of Passerine birds. This statistical method
has been followed by many authors, who, relying more upon quantity than
quality, have obscured the fact that the key to the present distribution
lies in the past changes of the earth's surface. However, with Wallace
begins the modern study of the geographical distribution of animals and
the sudden interest taken in this subject by an ever widening circle of
enthusiasts far beyond the professional brotherhood.

A considerable literature has since grown up, almost bewildering in its
range, diversity of aims and style of procedure. It is a chaos, with
many paths leading into the maze, but as yet very few take us to a
position commanding a view of the whole intricate terrain with its
impenetrable tangle and pitfalls.

One line of research, not initiated but greatly influenced by Wallace's
works, became so prominent as to almost constitute a period which may
be characterised as that of the search by specialists for either the
justification or the amending of his regions. As class after class of
animals was brought up to reveal the secret of the true regions, some
authors saw in their different results nothing but the faultiness of
previously est