The geographical distribution of animals, with a study of the relations ...

388 ZOOLOGICAL GEOGRAPHY. [part hi.where a fine range of mountains reaches, in the Colony of Victoria,the limits of perpetual snow. The west coast also possessesmountains of moderate height, but the climate is very dry andhot. The northern portion is entirely tropical, yet it nowherepresents the luxuriance of vegetation characteristic of the greatisland of New Guinea immediately to the north of it. Taken asa whole, Australia is characterized by an arid climate and a deficiencyof water; conditions which have probably long prevailed,and under which its very peculiar fauna and flora have been developed.This fact will account for some of the marked differencesbetween it and the adjacent sub-regions of New Guineaand the Moluccas, where the climate is moist, and the vegetationluxuriant ;of,and these divergent features must never be lost sightin comparing the different portions of the Australian region.In Tasmania alone, which is however, essentially a detachedportion of Australia, a more uniform and moister climate prevails;but it is too small a tract of land, and has been toorecently severed from its parent mass to have developed aspecial fauna.The Austro-Malay sub-region (of which New Guinea is thecentral and typical mass) is strikingly contrasted with Australia,being subjected to purely equatorial conditions,—a high, butuniform temperature, excessive moisture, and a luxuriant forestvegetation, exactly similar in general features to that whichclothes the Indo-Malay Islands, and the other portions of thegreat equatorial forest zone.Such a climate and vegetation, beingthe necessary result of its geographical position, must haveexisted from remote geological epochs with but little change, andmust therefore have profoundly affected all the forms of lifewhich have been developed under their influence. Around NewGuinea 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 weplace the Aru Islands, Mysol and Waigiou, with Jobie and theother Islands in Geelvinck Bay, all of which are connected withit by shallow seas ; they possess one of its most characteristicgroups, the Birds of Paradise, and have no doubt only recently (in