ertiary Era. The Oriental element came probably from Central and
Southern Asia, and in its march to Northern Europe it was joined by
local European migrations. For on our continent, too, animals originated
and spread in all directions from their centres of dispersal. A separate
chapter has been given to the _Alpine_ fauna, and another to that of
South-western Europe, which will be known by the name of the
_Lusitanian_ element. Finally, animals have also reached us from the
north, and in the fourth chapter the history of that remarkable
migration will be fully discussed under the title of the _Arctic_
element of the European fauna.

It is generally believed that Africa played an important role in the
peopling of our continent, but this is quite a mistake. The eminent
Swiss palaeontologist Ruetimeyer was quite right in saying (p. 42) that it
is much more probable that Morocco, Algeria, and Tunis were stocked with
animals by way of Gibraltar, and perhaps also by Sicily and Malta, from
Europe, than the South of Europe from Africa.

I have already referred to what are known as "centres of dispersion" of
animals, but before continuing to explain the general outline of this
book, it will be necessary to make a few additional remarks on the
subject.

Since every animal naturally tends to spread in every direction from its
original home--that is to say, from the place of its origin--the latter
should correspond with the centre of its range. And in any particular
group of animals the maximum number of species should be formed in the
area or zone which is the centre of its distribution. In the great
majority of instances this is probably the case, in the higher animals
perhaps less so than in the lower; still the rule must hold good that
the original home of a species is generally indicated by the centre of
its geographical distribution.

Take for example our familiar Badger (_Meles taxus_). It inhabits
Europe and Northern Asia. It is absent apparently from many parts of
Central Asia, but it appears again farther south in Palestine, Syria,
Persia, Turkestan, and Tibet. West Central Asia would be about the
centre of its range. That this corresponds to its place of origin is
indicated by the fact that the only three other Badgers known--viz., _M.
anakuma_, _M. leucurus_, and _M. albogularis_--are confined to Asia. If
we examine the fossil history of the genus, we find that the two most
ancient instances of the existence of Badge