Patterned specimens of C. semistriata and B. unifasciata are easily distinguished but the all-brown forms of each are very similar in size, shape and colour.
Maximum shell-height usually about 2.5 mm. Operculum very dark crimson (1), often looks black on live animal; outer face convex with silvery refringence. No spiral ridges.
Heights 3 mm, 2.9 mm & 2.8 mm. Swanage, Dorset, April 2016.
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