Southern Periwinkle

Ribbed Top Shells are often referred to as Periwinkles, but they are not related to the European shells of this name. Other top shells in this genus also live in south-eastern Australia and have various striped and checked patterns. All of them are grazers, feeding on algae

The thick, solid shell is imperforate. Its color is a lusterless ashen or whitish, obscurely marked with black zigzag lines and stripes, or with spiral articulated zones or with spiral stripes of black. Sometimes it is nearly unicolored. The spire is conical with an acute apex. The about five whorls are convex. The first one is eroded, the penultimate is very strongly spirally tricostate. The body whorl has about seven strong carinae. The aperture is oblique. The outer and basal lips are either thick and multilirate within, or rather thin and slightly furrowed at the places of the principal carinae. The short columella is oblique, subdentate at its base and at the insertion spreading in a strong callus upon the parietal wall.