Un-banded form, uniform claret-red, hence the synonym B. rubra.
1: whorl slightly convex, almost flat.
2: periphery of body-whorl not keeled on this specimen.
3: peristome of aperture white, no rib or labial varix.
4: adapical angle of aperture about 90°.
5: body-whorl about 70% of height (varies with age).
6: apical angle is about 45°.
7: shallow suture.
Height 2.5 mm. On Chondrus crispus in large pool sheltered from wave impact, at LWS. Llŷn, North Wales. October 2009.