Claim: The Mitromorpha usta, a species of sea snail, is characterized by its slightly oblique longitudinal ribs and its sulci which cut through the ribs.
Evidence: Mitromorpha usta is a species of sea snail, a marine gastropod mollusk in the family Mitromorphidae. The 12–14 longitudinal ribs are slightly oblique. The sulci (in the upper whorls 4, in the body whorl about 15) cut through the ribs and produce a somewhat granular appearance.