INVERTEBRATES 269 



Louring islands as far as Fiji ; (2) Euronotian, comprising Tasmania and the south- 

 eastern third of Australia ; (3) the Maorian, embracing New Zealand and the adjacent 

 islands ; (4) the West Australian. The Caroline, Marshall, and Marianne groups 

 are provisionally included in the Austro-Malay region, while the Hawaiian Archi- 

 pelago is regarded as an unattached region of great antiquity. Fiji, on the other 

 hand, is considered to be related as regards its fauna to the Papuan Archipelago or 

 to the tropical forest district of eastern Australia, and a Polynesian region is 

 accordingly not admitted ; Celebes being regarded as representing an unattached 

 or intermediate region. 



Apart from the tropical forest district of Queensland, Australia is characterised 

 by the poverty of its terrestrial molluscan fauna, a feature due, no doubt, to the 

 general dryness of this area. This is remarkably exemplified by the scarcity of 

 members of the group with operculated shells, which is, on the other hand, strongly 

 represented in Queensland and New Guinea. Although slugs of the typical genus 

 Limax have been introduced into the country, none is indigenous. A marked 

 negative feature common to the whole of Australia, Tasmania, and New Zealand 

 is the complete absence of the large marsh-dwelling gastropods of the genus 

 Ampullaria and of the pond-mussels of the genus Anodonta; a few species of 

 Unio are, however, to be found in the rivers. 



It has been observed that the country as a whole is poor in butterflies, 

 thereby presenting a striking contrast to tropical America, although the coast 

 districts of Queensland are better off in this respect, possessing some handsome 

 species of green Ornithoptera and other Malay types. Beetles are more abundant 

 throughout such parts of the country as are suited to their existence ; and it is 

 specially rich in the longicorn group. 



In common with those of South America and Madagascar, but unlike those of 

 Ethiopian Africa, the rivers of Australia and Tasmania are inhabited by crayfishes 

 belonging to the exclusively southern family Parastacidce ; the Australian genera 

 being Astacopsis and Eugceus. A Tasmanian species of the former, A. franJclini, 

 which is found in quite small streams, is the largest crayfish in the world, attaining 

 in some instances a weight of eight or nine pounds, and thus rivalling that of the 

 lobster. The distribution of this group of crustaceans is singularly like that of the 

 side-necked tortoises and the boa group of snakes ; and, in this case at any rate, 

 affords strong support to the theory of a former land-connection between Australia 

 and Madagascar on the one hand and South America on the other. 



