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192 GEOGRAPHICAL ZOOLOGY. [past iv.
extensive group of animals, now almost extinct. Many of the
forms continue to exist only in islands, removed from the severe
competition of a varied mammalian population, as in Madagascar
and the Antilles ;
while others appear to have escaped extermi-
nation either by their peculiar habits—as the various forms of
Moles; by special protection—as in the Hedgehogs; or by a resem-
blance in form, coloration, and habits to dominant groups in their
own district—as the Tupaias of Malay which resemble squirrels,
and the Elephant-shrews of Africa which resemble the jerboas.
The numerous cases of isolated and discontinuous distribution
among the Insectivora, offer no difficulty from this point of view
since they are the necessary results of an extensive and widely-
spread group of animals slowly becoming extinct, and continuing
to exist only where special conditions have enabled them to main-
tain themselves in the struggle with more highly organized forms.
The fossil Insectivora do not throw much light on the early
history of the order, since even as far back as the Miocene
period they consist almost wholly of forms which can be referred
to existing families. In North America they go back to the
Eocene period, if certain doubtful remains have been rightly
placed. The occurrence of fossil Centetidse in Europe, supports
the view we have maintained in preceding chapters, that the
existing distribution of this family between Madagascar and the
Antilles, proves no direct connection between those islands, but
only shows us that the family once had an extensive range.
Order IV.—CARNIVORA.
Family 23.—FELID^. (3 Genera, 14 Sub-genera, 66 Species.)
;