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 relics 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. 
REFERENCES. The following are the more important books on the 
subject of this chapter: Wallace, Geographical Distribution of Animals 
(London, 1876); Sclater, The Geography of Mammals (London, 1899) ; 
Lydecker, A Geographical History of Mammals (Cambridge, 1896) ; 
Beddard, A Tezt-book of Zoogeography (Cambridge, 1895); Trouessart, 
La Géographie Zoologique (Paris, 1890); Heilprin, The Geographical 
and Geological Distribution of Animals (London, 1887); Arldt, Die 
Entwicklung 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 full bibliography, will 
be found in the Atlas of Zoogeography, by Bartholomew, Clarke & 
Grimshaw (Edinburgh, 1911). 
1404 P 
