388 ZOOLOGICAL GEOGRAPHY. [pabt hi. 



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 



