Shell fusiform and turrited, many-keeled, of a greyish white colour, more or less spotted with black and ornamented with very finely granulated transverse striae ; whorls convex, doubly carinated round the periphery ; canal rather long. Few species exhibit a greater variety of growth and marking than this ; the periphery of the whorls is nevertheless constantly prominent and acute, and it is peculiar in being doubly carinated.