Slightly jagged spiral lines are visible crossing fine transverse growth lines. Magnification is usually needed to see them, especially on young specimens like this with weakly developed striae. These striae are diagnostic of H. navicula in northwest Europe, except the introduced aliens Haminella solitaria (Baltic, smooth spiral striae) and Haloa japonica. (Netherlands to Iberia and Mediterranean, very faint spiral striae). Shell height 5.4 mm from animal 9.2 mm long. Juvenile taken live with slurp gun from sand at base of <i>Zostera</i>, Dorset, England, September 2018, Leg. S. Trewhella.