i8 93 . FAUNA AND FLORA OF AUSTRALIA. 189 



to be restricted to the coast of Queensland, and that, proceeding from 

 south to north, the group becomes gradually richer in species and in 

 genera. In the New Zealand fauna the operculates are represented 

 by a tenth of the snail fauna as compared to none in Australia, except 

 Queensland, to one-sixth in Queensland, and one-third in New 

 Guinea. So far our investigation conforms to Wallace's theory, and 

 as that demands an origin in Australia for the New Zealand fauna, so 

 we expect the operculate land mollusca of New Zealand to be 

 descendants of those of Queensland. Here, however, facts rebel 

 against the theory, the New Zealand species being ranked under 

 Lagocheilus, Realia, and Hydvocena, while the Queensland ones are 

 contained in Georissa, Truncatella, Pupina, Cr.llia, Pupinella, Hedleya, 

 Ditvopis, Diplommatina, Leptopoma, and Heliciiia ; than which two faunas 

 could hardly be more distinct. 



Most European writers who have touched on the zoo-geography 

 of Australia have described the fauna and flora as falling into a 

 temperate and a tropical division, which again subdivide into eastern 

 and western sections. A little real experience proves these divisions 

 to be quite artificial. The dry interior, for example, is everywhere 

 inhabited by the same plants and animals, regardless of latitude or 

 longitude; examples are, the great red kangaroo among mammals, 

 the plain turkey, the mailer hen and the rosy cockatoo among birds, 

 the frog Notaden bennetti, the lizard Lygosoma monotropis, and the snakes 

 Pseudonaja nuchalis and Hoplocephalus nigriceps, among plants the pre- 

 dominance of salt-bush, spinifex, gidya (acacia), and Frenela. On the 

 eastern seaboard, the difference between north and south is that 

 between a conquering and invading fauna and flora and the indigenous 

 population where not exterminated or obscured by them. The types 

 encountered by a traveller in tropical Queensland, or rather in that 

 narrow belt of tropical Queensland hemmed in between the Cordillera 

 and the Pacific, all wear a foreign aspect. Among butterflies the 

 Ornithoptera, among reptiles the crocodile, among birds the cassowary 

 and rifle bird, among mammals the tree kangaroo and the cuscus, and 

 among plants the profusion of epiphytic orchids and of palms, all point 

 to a northern origin. In the heart of a great Queensland " Scrub " a 

 naturalist could scarcely answer from his surroundings whether he 

 were in New Guinea or Australia. 



Late in the Tertiary Epoch, as I read the record, Torres Straits, 

 now only a few fathoms deep, was upheaved, and across this bridge 

 there poured into Australia a stream of Papuan life. Between the 

 coastal range and the sea as far as the tropics the irruption flowed in 

 undiminished strength ; on reaching the border of N.S.W. the cooler 

 climate diminished its vigour, and at the Clarence River, N.S.W., 

 with few exceptions, it found its southern limit. Within this area grow 

 side by side, like oil and water — touching yet not commingling, two 

 distinct vegetations, the dense Papuan jungle called " Scrub " by the 

 Queenslanders, which has usurped every rich volcanic upland and 



