S.A. NAT.. 
VOL. XVIII, No. 2. 
By TOM IREDALE. 
9. 
Phylum Mollusca. 
This Phylum includes all molluscan animals related to 
Oysters, Cockles, Mussels, Whelks, Winkles, Sea Devils, Cuttles, 
Sea Butterflies, and the majority of objects known as Shells. The 
common Snail represents a series which has taken to living on 
land, the great majority of shells belonging to the sea. These 
land-living forms, as they breathe air, have been classed together 
as a Subclass Pulmonata, of a larger Class Gastropoda. Another 
large Class, Pelecypoda, includes the bivalve shells such as 
Oysters, Mussels, and none of these live on land, but a number 
are found in rivers, lakes, etc., and are part of the Freshwater 
Mollusca, which, however, also includes a number of shells 
belonging to the Class Gastropoda. Then in order to bring 
■system into the recognition of these land Snails, many of which 
are much alike superficially, though are of different origin, a 
great deal of subdivision is necessary. Thus we arrive at an 
Order Stylommatophora, to which all the Centralian Land Shells 
belong. The first family, Vertiginidae, includes a series of small 
pupoid molluscs, which are difficult to distinguish without micro- 
scopic examination, the largest being only about a quarter of an 
inch long. 
Although I followed Pilsbry in placing all the Australian 
Pupoid shells in one family, Vertiginidae^ further study has 
shown that this was obviously incorrect, and I find that recent 
specialists have differentiated the groups with family rank, even 
as Pilsbry himself had suggested. Thiele, indeed, followed Pils- 
bry, but he was throughout ultra conservative, save in his own 
researches. Steenberg, from anatomical investigation, allow'ed 
family rank to most of the groups, agreeing with Pilsbry’s sub- 
famdies. Under Steenberg’s scheme Australbinula would belong 
to one family and Themapupa and Omegapilla to another. 
Genus Australbinula. 
1916. Australbmula Pilsbry, Man. Conch. (Trvon), 2nd Ser. 
Vol. XXIV, (93), p.ll, December 18. 
Orthotype {Gastrocopta) rossiteri, 
1917. Atistralbinula Pilsbry, Man. Conch. (Tryon), 2nd Ser. 
Vol. XXIV, (94), pp. 155/166, July 18. 
Orthotype Gastrocopta hedleyi VAshry—rossiteri supra. 
A genus of small Pupoid shells, generally dextral, faintly 
striate, about 3 mm. long, with the small mouth almost closed by 
teeth blocking the aperture; the teeth generally number five to 
seven, a large one on the columella, one to three, called the 
