442 ZOOLOGICAL GEOGRAPHY. {PART III. 
longing to a different family, the Casurariide. To the right are 
a pair of crested pigeons (Ocyphaps lophotes), one of the many sin- 
gular forms of the pigeon family to which the Australian re- 
gion gives birth. In every other part of the globe pigeons are 
smooth-headed birds, but here they have developed three dis- 
tinct forms of crest, as seen in this bird, the crowned pigeon 
figured in Plate X., and the double-crested pigeon (Lopholemus 
antarcticus). The large bird on the tree is one of the Australian 
frog-mouthed goat-suckers (Podargus strigoides), which are 
called in the colony “ More-pork,” from their peculiar ery. They 
do not capture their prey on the wing like true goat-suckers, but 
hunt about the branches of trees at dusk, for large insects, and 
also for unfledged birds. A large kangaroo (Macropus giganteus) 
is seen in the distance ; and passing through the air, a flying 
opossum (Petawrus sciureus), a beautiful modification of a marsu- 
pial, so as to resemble in form and habits the flying squirrels 
of the northern hemisphere. 
ITT. The Pacifie Islands, or Polynesian Sub-region. 
Although the area of this sub-region is so vast, and the 
number of islands it contains almost innumerable, there is a 
considerable amount of uniformity in its forms of animal life. 
From the Ladrone islands on the west, to the Marquesas on the 
east, a distance of more than 5,000 miles, the same characteristic 
genera of birds prevail; and this is the only class of animals on 
which we can depend, mammalia being quite absent, and reptiles 
very scarce. The Sandwich Islands, however, form an exception 
to this uniformity; and, as far as we yet know, they are so 
peculiar that they ought, perhaps, to form a separate sub-region. 
They are, however, geographically a part of Polynesia; and a 
more careful investigation of their natural history may show 
more points of agreement with the other islands. It is therefore 
a matter of convenience, at present, to keep them in the Poly- 
nesian sub-region, which may be divided into Polynesia proper 
and the Sandwich Islands. 
Polynesia proper consists of a number of groups of islands of 
some importance, and a host of smaller intermediate islets. 
