What is "pleurotomarioidea"

Pleurotomarioidea is a superfamily of small to large marine gastropods included in the Vetigastropoda.

These are the slit shells, originally named Pleurotomariacea, in keeping with the convention for naming superfamilies at the time. This updated version of the name for the taxon is usually used by students of the living Mollusca. Paleontologists often still use the name Pleurotomariacea instead.