252 
GEOGRAPHICAL ZOOLOGY. 
[part IV. 
in form the flying squirrels'* of North America and India, hut 
often no larger than a ipouse; the beautiful dormouse-like 
Dromitiw, one species of which is only 2J 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 Phalangistidae not only range over all Australia and 
Tasmania, but over the whole of the Austro-Malayan sub-region 
from New Guinea to the Molucoas 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 ; Cuscus (8 sp.), woolly phalangers, 
New Guinea, North Australia, Timor, Moluccas and Celebes ; 
Petaurista (1 sp.) large flying phalanger, East Australia ; 
Bdideus (5 sp.), flying opossums, South, East, and North Aus- 
tralia, New Guiana and Moluccas ; Acrobata (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.— PHASCOLOMYXDzE, (1 Genus, 3 Species.) 
General Distribution. 
X F.OTROFICAL 
SlB-REGIONS, 
Nearctic 
Sub-regions. 
[ PAT..E ARCTIC I 
Sub-regions. 
Ethiopian 
Sub-regions. 
1 Oriental 
Sub-regions. 
1 Australian 
Sub-regions. 
