Flexible periostracal flap (1) extends beyond outer lip. In arid conditions, the flap is glued to rock with dried mucus, and the foot withdrawn from contact with the substrate.
Black rim of opercular lobe (2) shows through translucent tear-shape spiral operculum. Dorsal (3) and ventral (4) surfaces of foot. Height 7.5 mm.
April 2012. Portland Bill, Dorset, England.