fi.A. NAT., 
VOL. XVIII, No. 2. By TOM IRBOALU 
Stenopylis hemiclausa. PI. I, fig- 20. 
1894. Planispira hemiclausa Tate, Trans. Roy. Soc. South Austr., 
Vol. XVIII, p.192, November. Central Australia. 
3896. Rep. Horn. Sci. Exped. Cent. Austr., pt. II, Zool., p.l85, 
pi. XVII, fig. I, February. Ilpilla Gorge, Spencer Gorge 
etc., C.A. 
1896. Microphyura hemiclausa Hedley, id., ib., p.221, fig. C. 
The distribution of this form is very peculiar as it appears 
to range along the Queensland coast and then in the interior. 
Family Microcystidae. 
The South Australian “Zonitids” are unknown anatomically, 
-and therefore their relationships are problematical. In the mean- 
while the few species are alloted to the Microcystidae with doubt 
.as two families may even be represented. 
Genus Echonitor nov. 
Type Thalassia cyrtochila Gude. 
Gude later introduced Nitor to replace Thalassia, the type 
being given as subrugata Reeve, an Oxleyan form. As the shell 
of cyrtochila differs in form completely from Nitor, a name is 
necessary until the animals are examined. In shell characters 
the South Australian shell is more like the Queensland Micro- 
■cystids such as rustica with which it was long confused. The 
shell is depressedly subglobose, thin, glossy but not shining, 
whorls few, well rounded, sutures a little impressed, apical whorls 
smooth, umbilicus minute, hidden by the reflected columella. 
Echonitor cyrtochilus. 
1905. Thalassia cyrtochila Gude, Journ, Malac. Vol. XII, p.l2, 
pi. Ill, fig. 2, a.b. April 7. Long Reef, South Australia. 
A cotype is golden brown, and Gude wrote ‘S'ery finely 
arcuately striated, densely covered by excessively minute spiral 
lines. Under a strong lens these are not discernible so that the 
shell is smooth to all appearance. 
Many specimens from various places disagree In color and 
form, being pale greenish and more conical, less globose. The 
umbilicus is more open, and as these are well known in collections 
under the name euroxesta, that is here used, the type locality 
being selected as Franklin Harbour, Eyre’s Peninsula. The 
typical specimen measures 11.5 mm. in breadth by 8 mm. in 
height. PI. I, fig. 19. 
