From unstable boulders on exposed shore. Body whorl height (1) 86% of shell height. Oval aperture, base slightly flared (2). Adapical angle c. 90º (3). Palatal lip crenulated by grooves on outer surface (4). Columellar lip wide (5). Substantial glaze forms parietal lip (6). Broad slightly curved (7) or flat (8) strap-like, spiral ribs with narrow, incised grooves. Dark spiral lines confined to grooves. Dark marks (9) at ends of grooves on palatal lip. Pale-brown operculum, translucent showing flesh within. 9.1 mm high. Anglesey, March 2014.