As Siphonaria virgulata (Hedley)
Shell rather thin, almost symmetrical, suborbicular, apex sub-central. Colour: interior with a central bluish callus, surrounded by a broad dark chocolate zone fading externally to pale brown with white dashes on the margin; exterior with apex dark brown, riblets white, their interstices irregularly chocolate. Sculpture : about seventy radial riblets, which narrow and waver as they ascend. Their size is irregular, about a third or fourth riblet being larger than the rest, margin finely denticulate. Siphonal fold slight and shallow. Length, 21; breadth, 19; height, 9mm.
Hab.—Terrigal, Sydney, and Twofold Bay; in the wash of the suif on ocean-beaches (self).