There is a line of commashaped spots which extend from the summit into the flat space anterior to it.

The keels are equally spaced, the fourth being at the periphery, while the first is a little further from the summit than it is from its neighbor anteriorly.

The periphery and the base are well rounded, the latter broadly umbilicated and marked by 10 depressed spiral cords which are truncated posteriorly and slope gently anteriorly.

These cords are crossed by closely spaced riblets which give them a peculiarly notched appearance.

[4] This marine species occurs off Cape of Good Hope, South Africa.