388 ZOOLOGICAL GEOGRAPHY. [Part m1, 
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where a fine range of mountains reaches, in the Colony of Vic- 
toria, the limits of perpetual snow. The west coast also possesses 
mountains of moderate height, but the climate is very dry and 
hot. The northern portion is entirely tropical, yet it nowhere 
presents the luxuriance of vegetation characteristic of the great 
island of New Guinea immediately to the north of it. Taken as 
a whole, Australia is characterized by an arid climate and a de- 
ficiency of water ; conditions which have probably long prevailed, 
and under which its very peculiar fauna and flora have been de- 
veloped. This fact will account for some of the marked differ- 
ences between it and the adjacent sub-regions of New Guinea 
and the Moluccas, where the climate is moist, and the vegetation 
luxuriant ; and these divergent features must never be lost sight 
of, in comparing the different portions of the Australian region, 
In Tasmania alone, which is however, essentially a detached 
portion of Australia, a more uniform and moister climate pre- 
vails; but it is too small a tract of land, and has been too 
recently severed from its parent mass to have developed a 
special fauna. 
The Austro-Malay sub-region (of which New Guinea is the 
central and typical mass) is strikingly contrasted with Australia, 
being subjected to purely equatorial conditions,—a high, but 
uniform temperature, excessive moisture, and a luxuriant forest 
vegetation, exactly similar in general features to that which 
clothes the Indo-Malay Islands, and the other portions of the 
great equatorial forest zone. Such a climate and vegetation, being 
the necessary result of its geographical position, must have 
existed from remote geological epochs with but little change, and 
must therefore have profoundly affected all the forms of life 
which have been developed under their influence. Around New 
Guinea as a centre are grouped a number of important islands, 
more or less closely agreeing with it in physical features, climate, 
vegetation, and forms of life. In most immediate connection we 
place the Aru Islands, Mysol and Waigiou, with Jobie and the 
other Islands in Geelvinck Bay, all of which are connected with 
it by shallow seas ; they possess one of its most characteristic 
groups, the Birds of Paradise, and have no doubt only recently (in 
