 The whole surface is covered by strongly marked revolving cinguli, which cross both the ribs and their interspaces, and thicken so as to form small, rounded nodules where they cross the ribs.These are separated by interspaces of about the same width, in the middle of which there is a much smaller, thin revolving cingulus, alternating pretty regularly with the larger ones around the periphery.On the anterior part of the body-whorl, and sometimes at the periphery, there are two or three small revolving cinguli in some of the interspaces.