Habitat: Rocky shorelines Natural History Notes: Further research may synonymize Characteristics: Maximum reported size: 31 mm. The moderately elevated shell is ovate and narrows anteriorly. The exterior is usually mostly reddish brown with some white, and major ribs are often brownish. The interior is whitish, with a light to dark brown callus surrounding the orifice. The ovate or nearly circular keyhole is located anteriorly. One of the approx. nine major radial ribs is centered on the anterior slope. These ribs are crossed by concentric ridges to form an gnarled sculpture of irregular nodules.