Mohnia blakei

The lower whorls are crossed by numerous rather straight, obtuse ribs, separated by intervals of about their own breadth.

They are faintly marked and oblique on the concave subsutural band, but form another circle of obtuse tubercles just below the suture.

Below this there are pretty regular, well-developed revolving cinguli, which are rounded and separated by rather wide intervals, and cross both ribs and interspaces, but in crossing the ribs they become more prominent and form oblong nodules on the upper part of the whorl.

On the lower part of the whorl and siphon they are a little wider, more spaced, and roughened only by the raised lines of growth.

The subsutural band is strongly marked, broad and decidedly concave, and is covered with slightly curved, oblique lines of growth and faint ribs, and has a single, small, revolving cingulus in the middle.