Shell narrow, elongated, cylindrical, thin and glossy. Colour white. Sculpture: growth lines hardly perceptible, encircled by fine, close, incised lines; almost effaced medially, and wider spaced posteriorly. The crown concave, with a narrow axial perforation, partly roofed by a callus arch. Aperture as long as the shell, narrow above, expanded and effuse below; lined on the inner side by a sheet of callus ragged at the edge. Columella thickened, with a prominent fold, behind which a furrow runs up under the lip callus. Length, 11,5 mm.; breadth, 4,5 mm.
The " Thetis" procured this off the Manning River in 22 fathoms; and in 63-75 fathoms off Port Kembla. I have taken it on the beach in Middle Harbour.

The narrowly perforate summit easily distinguishes this from C. arachis, Q. and G., the only Australian shell likely to be taken for it.
The Chinese C. involuta, A. Ad., appears to resemble it more.