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252 GEOGRAPHICAL ZOOLOGY. [part iv.
in form the flying squirrels of North America and India, but
often no larger than a mouse ; the beautiful dormouse-like
.Dromicim, one species of wliich is only 2^ inches long or less
than the harvest-mouse ; and the little Tarsipes, a true honey-
sucker with an extensile tongue, and of the size of a mouse.
These extreme modifications and specializations within the range
of a single family, are sufficient to indicate the great antiquity
of the Australian fauna ; and they render it almost certain that
the region it occupied was once much more extensive, so as
to supply the variety of conditions and the struggle between
competing forms of life, which would be required to develop so
many curiously modified forms, of which we now probably see
only a remnant.
The PhalangistidcC not only range over all Australia and
Tasmania, but over the whole of the Austro-Malayan sub-region
from New Guinea to the Moluccas and Celebes. The distribu-
tion of the genera is as follows :
—
Phascolardos (1 sp.), the
koala, East Australia ; Phalangista (5 sp.), East, South, and West
Australia, and Tasmania ; Cusctis (8 sp.), woolly phalangers.
New Guinea, North Australia, Timor, Moluccas and Celebes ;
Petaurista (1 sp.) large flying phalanger, East Australia ;
Belideus (5 sp.), Iflying opossums. South, East, and North Australia,
New Guiana and Moluccas ; Acrohata (1 sp.), pigmy
flying opossum. South and East Australia; Dromicia (5 sp.),
dormouse-phalangers, West and East Australia, and Tasmania;
Tarsipes (1 sp.). West Australia.
Thylacoleo, a large extinct marsupial of doubtful affinities,
seems to be somewhat intermediate between this family and the
kangaroos. Professor Owen considered it to be carnivorous, and
able to prey upon the huge Diprotodon, while Professor Flower
and Mr. Gerard Krefft, believe that it was herbivorous.
Family 82.—PHASCOLOMYID^. (1 Genus, 3 Species.)
Neotropical
Si'B-REOIONS.
General Distribution.
Nearctic Pal/EARctic Ethiopian I Oriental I Australian
Sub- REGIONS.
I
Sub-regions.
I
Sub-regions. Sub-reoions. Sub-regions.