ZOOGEOGRAPHICAL REGIONS 225 



poor, but the presence of the very primitive dipnoan 

 fish Ceratodus is important. This fish, now found only 

 in the rivers of Queensland, lived in the far-off Devonian 

 period in the seas of the northern hemisphere, and is 

 one of the curious rehcs of the Australian continent. 

 Another is a mussel called Trigonia, now found only 

 off Australian coasts, but once abundant in the Jurassic 

 and Cretaceous seas of Europe. Still another curious 

 relic is the mountain shrimp (Anaspides), a primitive 

 type of crustacean found only in the mountain region 

 of Tasmania, and apparently closely related to forms 

 found fossil in Carboniferous and Permian beds in 

 Europe and North America. These old-fashioned forms 

 are perhaps in some respects even more striking than 

 the marsupials in suggesting the long isolation of 

 Australia, and the extraordinary differences between 

 its fauna and that of the rest of the world. 



Rbfebbnces. The following are the more important books on the 

 subject of this chapter : Wallace, Oeographical Distribution of Animals 

 (London, 1876) ; Sclater, The Oeogra/phy of Mammals (London, 1899) ; 

 Lydecker, A Oeographical History of Mammcds (Cambridge, 1896); 

 Beddaid, A Text-took of Zoogeography (Cambridge, 1895) ; Trouessart, 

 La Oiographie Zoologique (Paris, 1890) ; Heilprin, The Oeographical 

 and Geological Distribvtion of Animals (London, 1887) ; Arldt, Die 

 EntitticJclung der Kontinente und ihrer Lebewelt (Leipzig, 1907). See also 

 Geoffrey Smith, A Naturalist in Tasmania (Oxford, 1909), for a dis- 

 cussion of the origin of the Australian fauna. A very elaborate series of 

 plates, with a considerable amount of text and a fuU bibliography, will 

 be found in the Adas of Zoogeography, by Bartholomew, Clarke & 

 Grimshaw (Edinburgh, 1911). 



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