Shell profiles.
1: Height 12.5 mm, breadth 14 mm. H. 89%. of B.
2: Height 16 mm, breadth 19 mm. H. 84% of B.
3: Height 27 mm, breadth 26.5 mm. H. 102% of B.
Ratio height: breadth increases when full grown; height often equals or exceeds breadth.
Ground colour of shells, shades of buff. Large adult has eroded spire exposing silver nacre.
April 2012. Weymouth, Dorset.