[1] The white, minute shell forms a depressed sphere which is equally raised above and below.

They rapidly enlarge, so that the body whorl considerably exceeds in size the rest of the shell.

The slit is long and central, equal in width, with upturned edges.

The aperture is nearly circular, but somewhat angulated where it is united to the body whorl below the peripheral keel.

[2] This species occurs in European waters, the Caribbean Sea and the Lesser Antilles.