408 ZOOLOGICAL GEOGRAPHY. [part hi. 



out the important facts of distribution. All that can be done 

 here is to note the characteristic and peculiar genera, and any 

 others presenting features of special interest. 



In the great family of the snails (Helicidse), the only genera 

 strictly confined to the region are, Partula, now containing above 

 100 species, and ranging over the Pacific from the Solomon Isles 

 on the west, to the Sandwich Islands and Tahiti on the east ; 

 and Achatinella, now containing nearly 300 species, and wholly 

 confined to the Sandwich Islands. Pfeifferia is confined to the 

 Philippine Islands and Moluccas ; Cochlostyla to the Indo-Malay 

 Islands and Australia ; Bulimus occurs in most of the insular 

 groups, including New Zealand, but is absent from Australia. 



Among the Aciculidse, the widely-scattered Truncatella is the 

 only genus represented. Among Diplommatiniche, Diplommatina 

 is the characteristic genus, ranging over the whole region, 

 and found elsewhere as far as India, with one species in 

 Trinidad. The extensive family Cyclostomidse, is not well 

 represented. Seven genera reach the Austro-Malay Islands, 

 one of which, Registoma, is confined to the Philippines, Moluc- 

 cas, New Caledonia, and the Marshall Islands. 0?7iphalotropis 

 is the most characteristic genus, ranging over the whole region ; 

 Gallia is confined to the Philippines, Ceram, and Australia ; 

 Realia to New Zealand and the Marquesas. The genus Helicina 

 alone represents the Helicinidas, and is found in the whole region 

 except New Zealand. The number of species known from 

 Australia is perhaps about 300; while the Polynesian sub-region, 

 according to Mr. Harper Pease, contains over 600 ; the Austro- 

 Malay Islands will furnish probably 200 ; and New Zealand 

 about 100; making a total of about 1,200 species for the whole 

 region. 



AUSTEALIAN SUB-EEGIONS. 



Pew of the great zoological regions comprise four divisions so 

 strongly contrasted as these, or which present so many interesting 

 problems. We have first the Austro-Malay Islands, an equatorial 

 forest-region teeming with varied and beautiful forms of life ; 

 next we have Australia itself, an island-continent with its satellite 



