408 ZOOLOGICAL GEOGRAPHY. [PART 111. 
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 (Helicide), 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 Aciculide, the widely-scattered Truncatella is the 
only genus represented. Among Diplommatinide, 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 Cyclostomide, 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. Omphalotropis 
is the most characteristic genus, ranging over the whole region ; 
Callia is confined to the Philippines, Ceram, and Australia ; 
Realia to New Zealand and the Marquesas. The genus Helicina 
alone represents the Helicinide, 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. 
‘ AUSTRALIAN SUB-REGIONS. 
Few 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 
