[1] (Original description by Verrill) As at present understood, this genus is intended to include those species which have a rather broad and very distinct subsutural band, crossed by excurved lines of growth corresponding to the form of the posterior sinus of the lip, which is situated a little below the suture and is always pretty well-developed, but is sometimes broad and shallow, and at other times narrower and very deep.

The outer lip is always thin and sharp, without any appearance of a varix, nor is there any deposit of callus on the body whorl, in front of the aperture.

The protoconch differs in sculpture, and usually in color, from the rest of the whorls, and is generally minutely cancellated by fine raised lines running obliquely in opposite directions.

The remaining whorls are elegantly sculptured by longitudinal ribs and revolving cinguli, and usually have a distinct shoulder or carina, which is frequently nodulous, below the subsutural band.

The adult shell shows a small blunt protoconch of several (usually) swollen whorls, closely arcuately axially ribbed.