1: involute spire, sunk below encompassing final whorl, resembles an umbilicus. No suture visible as spire involute.
2: internally, all whorls open to and spiral round wide central cavity instead of solid columella.
3: nacre deposited by mantle just within the aperture. Brownish periostracum is protected from erosion where nacre overlies it. In this worn specimen some of the nacre has flaked off. Height 21.2mm. Strandline shell, spiral lines difficult to see. South Devon, England. May 2017. Leg. H. Morgenroth & K. Rose.