214 
not pearly inside the family reference should be to Cyclostre- 
matide, ~ position confirmed by my personal knowledge of its 
operculum. Another species of dubious generic location is Liotva 
Loddera, which, because of its thickened aperture, has a Liotia- 
like aspect ; but its vitreous test, in the absence of other charac- 
ters, makes it desirable to relegate it also to Cyclostrematide. 
Having applied the above-mentioned conchological tests to 
many of our reputed species of these two families, I hope that 
my verdicts thereon may facilitate the preparation of a complete 
revision of them. 
FAMILY CYCLOSTREMATID. 
Cyclostrema is a heterogeneous assemblage of species, embracing 
such divergent characters as— 
1. TexturE—a, porcellonous and thick, as in C. mucans ; 
b, translucent and thin, as in C. Tatez. 
2. SHAPE—a, turbinate, as C. tenera, Jeffreys, and C. conica, 
‘ Watson ; 0b, discoid, as C. nivea, A. Ad.; ¢, planorbiform, 
as C. cyclotina, A. Ad. 
3. APERTURE—da, simple, as in C. Jatez; 6, thickened, as in 
C. micans ; c, varicosely margined, as in C. Loddere. 
4. Umpiticus—a, wide in C. Jatei; 6, almost obliterated in 
C. micans. 
5. PERITREME continuous or incomplete. 
These multifarious elements indicate that Cyclostrema, in an 
extended sense, is heterogeneously composed, and in my treatment 
of the Australian species I have endeavoured to arrange them in 
genera and sections best in accord with morphological charac- 
teristics—anatomical features still remain unascertained ; never- 
theless, I have added difficulties by the inclusion of three species 
of doubtful classificatory position. 
Genus CycLostrEeMA, : Marryatt, 1818. 
Shell depressed ; test thin, hyaline, usually spirally lined or 
ridged ; aperture simple ; umbilicus open. 
The genus Vitrinella, C. B. Adams, does not appear to me to 
be distinct from the typical Cyclostrematids. 
SECTION CYCLOSTREMA, S. S. 
The characters of the genus. 
Section Tupionta, A. Adams, 1864. 
Shell turbinate ; thin, opaque-white, and usually inornate. 
The genus Cirsonella, Angas, which was placed provisionally 
by its author among Trochide, is, in my opinion, reducible to 
this section. Fischer, Man. Conch., and Tryon, Man. Conch., 
X., p. 16, place it subgenerically under Zinostoma. Tinostoma 
is not considered by me a member of the family, 
