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234 GEOGRAPHICAL ZOOLOGY. [part IV.
Family 60.—CASTOEID^. (1 Genus, 2 Species.)
Is'eotropical Nearctic
Sub-regions. Sub-regions.
General Distribution.
PAL.EARCTIC
SUB-REGION.S.
1 .2.3 .4 -3-
I
Ethiopian
Sub-regions.
Oriental
sub-kegions.
AOSTRALIAN
SUB-RKGIONS.
The Beavers, forming the genus Castor, consist of two species,
the American {Castor canadensis) ranging over the whole of
North America from Labrador to North Mexico ; while the
European {Castor fiber) appears to be confined to the temperate
regions of Europe and Asia, from France to the Eiver Amoor,
over which extensive region it doubtless roamed in prehistoric
times, although now becoming rare in many districts.
Extinct Castoridce.—Extinct species of Castor range back
from the Post-pliocene to the Upper Miocene in Europe, and to
the Newer Pliocene in North America. Extinct genera in Europe
are, Trogontherium, Post-Pliocene and Pliocene; Chalicomys,
Older Pliocene; and Steneofiber, Upper Miocene. In North
America Castoroides is Post-Pliocene, and Palmcastor, Upper
Miocene. The family thus first appears on the same geological
horizon in both Europe and North America.
Family 61.—SCIUPJD.^.—(8 Genera, 180-200 Species.)
General Distribution.
Neotropical Nearctic Pal^arctic i Ethiopian Oriental i Australian
SuB-REGioN,s. Sub-regions. Sub-hegions. Sub-regions. Sub-eegions. Sub-eeGions.
2.3 — 1 .2.3.4 I
1 .2.3.4 1.2.3 1.2.3.4
The Squirrel family, comprehending also the marmots and
prairie-dogs, are very widely spread over the earth. They are
especially abundant in the Nearctic, Pal^arctic, and Oriental
regions, and rather less frequent in the Ethiopian and Neotro-
pical, in which last region they do not extend south of Paraguay.
They are absent from the West Indian islands, Madagascar, and
Australia, only occurring in Celebes which doubtfully belongs
to the Australian region. The genera are as foUows :—