in-eaters, bee-eaters, and sun-birds of Africa. Parts of
South-temperate America, South Africa, and South Australia, correspond
closely in climate; yet the birds and quadrupeds of these three districts
are as completely unlike each other as those of any parts of the world that
can be named.

If we visit the great islands of the globe, we find that they present
similar anomalies in their animal productions, for while some exactly
resemble the nearest continents others are widely different. Thus the
quadrupeds, birds and insects of Borneo correspond very closely to those of
the Asiatic continent, while those of Madagascar are extremely unlike
African forms, although the distance from the continent is less in the
latter case than in the former. And if we compare the three great islands
Sumatra, Borneo, and Celebes--lying as it were side by side in the same
ocean--we find that the two former, although furthest apart, have almost
identical productions, while the two latter, though closer together, are
more unlike than Britain and Japan situated in different oceans and
separated by the largest of the great continents.

These examples will illustrate the kind of questions it is the object of
the present work to deal with. Every continent, every country, and every
island on the globe, offers similar problems of greater or less complexity
and interest, and the time has now arrived when their solution can be
attempted with some prospect of success. Many {7} years study of this class
of subjects has convinced me that there is no short and easy method of
dealing with them; because they are, in their very nature, the visible
outcome and residual product of the whole past history of the earth. If we
take the organic productions of a small island, or of any very limited
tract of country, such as a moderate-sized country parish, we have, in
their relations and affinities--in the fact that they are _there_ and
others are _not_ there, a problem which involves all the migrations of
these species and their ancestral forms--all the vicissitudes of climate
and all the changes of sea and land which have affected those
migrations--the whole series of actions and reactions which have determined
the preservation of some forms and the extinction of others,--in fact the
whole history of the earth, inorganic and organic, throughout a large
portion of geological time.

We shall perhaps better exhibit the scope and complexity of the subject,
and sh