Ma'ili Pt., Oahu, 4 feet, 27 mm 

Uncommon on ledges deeper than 40 feet where it grazes upon live coral, but finds shelter away from it.  Rounded axial ribs with spiral sculpture of overlapping scales and white aperture, often encrusted by coralline algae.  Attains 2 inches, 50 mm.  The closely related Coralliophilia bulbiformis is lighter, with longer spines, and a lilac aperture.  Reported as Coralliophila erosa in Kay, 1979.