South Australian Shells/. 
S.A. NAT., VOL. XVI. 
Dec. 15 , 1934 . 
yellow predominating; spire very short, conic, apex usually per- 
fect and acute, often ruddy; whorls five, slightly convex, very 
rapidly increasing, spirally strongly costate, thirteen or fourteen 
ridges on the last whorl; body-whorl slightly descending at the 
aperture, not eroded at the base; aperture large, oblique; outer lip 
margined within with yellow and black, followed by a nacreous 
and then by an opaque white thickening which more or less 
contracts the aperture and which is more or less notched at 
about the place of the periphery; columella white, bidenticulate 
below. Height 20-22, diam. 23-25 mm. Rather common, gre- 
garious under rocks between tide marks, South Australia and 
Western Australia. Very common in Tasmania and Victoria. 
(Type locality- — South Australian and Tasmanian coasts). The 
more prominent characters are the strong spiral ribs and the 
thick outer layer of yellow and purplish-black, or of black veined 
with yellow, which usually assumes a tessellated pattern. Some- 
times the black predominates to the almost entire exclusion of 
yellow, and specimens also occur in which the black is scarcely 
visible on the surface. Wood published no description of his 
cone emerald , consequently the older conchologists preferred 
Quoy & Gaimard’s striolata. 
A. rudis Gray 1826 ( Monodonta ) (= M. melanoloma 
Menke 1843: = Trochocochlea chloropoda Tate 1878-79). PI. 1, 
fig. 4. “'I'he Roughened Austrocochlea.” .Shell much like Austro- 
cochlea torn Cotton & Godfrey, but without longitudinal plica- 
tions and sutural constrictions; very thick; yellowish-white or 
gray; surface marked with curved striae of growth, and under 
the lens with numerous longitudinal striae; outer lip thin; broad- 
ly bevelled on inner side, of a black colour; perlaceous interior 
with nine longitudinal, narrow, roundly elevated porcellanous 
ribs; columella white, broad, arched; under side of body whorl 
black. Aged examples have the elongate -turbinate shape of 
A. torn . Height 25, diam. 25 mm. On rocks below tide marks, 
rather common, where present, Coy mb r a, Point Sinclair, Wilson’s 
Bluff. Venus Bay, Southern Yorke Peninsula, Kangaroo Island, 
and west coast of South Australia. Also Western Australia — 
King George Sound, Geraldton, Hopetoun, Bunbury, Rottnest, 
Ellensbrock, Yallingup, Albany. The outer lip is bordered by 
a narrow yellow or white, followed bv a black strip; the colu- 
mella is short, oblique, substraightened, white, dilated upon the 
parietal wall; slightly pitted at the place of the umbilicus, sub- 
concave. Distinguished from all other S.A. species of Austro- 
cochlea bv the entire lack of spiral sculpture. The species re- 
sembles Nerita melano tragus on superficial examination, espec- 
ally in life when crawling over rock surfaces. Of course, it is 
