sectivores, although as old as any
Placentalia, are cosmopolitan excepting South America and Australia;
Stags and Bears, as examples of comparatively recent Arctogaeans, are
found everywhere with the exception of Ethiopia and Australia. Each of
these groups teaches a valuable historical lesson, but when these are
combined into the establishment of a few mammalian "realms," they mean
nothing but statistical majorities. If there is one at all, Australia is
such a realm backed against the rest of the world, but as certainly it
is not a mammalian creative centre!

Well then, if the idea of generally applicable regions is a mare's nest,
as was the search for the Holy Grail, what is the object of the study
of geographical distribution? It is nothing less than the history of the
evolution of life in space and time in the widest sense. The attempt to
account for the present distribution of any group of organisms involves
the aid of every branch of science. It bids fair to become a history of
the world. It started in a mild, statistical way, restricting itself to
the present fauna and flora and to the present configuration of land
and water. Next came Oceanography concerned with the depths of the seas,
their currents and temperatures; then enquiries into climatic changes,
culminating in irreconcilable astronomical hypotheses as to glacial
epochs; theories about changes of the level of the seas, mainly from the
point of view of the physicist and astronomer. Then came more and more
to the front the importance of the geological record, hand in hand with
the palaeontological data and the search for the natural affinities, the
genetic system of the organisms. Now and then it almost seems as if the
biologists had done their share by supplying the problems and that the
physicists and geologists would settle them, but in reality it is not
so. The biologists not only set the problems, they alone can check the
offered solutions. The mere fact of palms having flourished in Miocene
Spitzbergen led to an hypothetical shifting of the axis of the world
rather than to the assumption, by way of explanation, that the palms
themselves might have changed their nature. One of the most valuable
aids in geological research, often the only means for reconstructing the
face of the earth in by-gone periods, is afforded by fossils, but only
the morphologist can pronounce as to their trustworthiness as witnesses,
because of the danger of mistaking analogous