Obliquely oval, inequilateral, inflated; umbo very prominent, ante-median; hinge line straight; anterior margin obliquely descending; colour whitish, with four radial flames of chestnut beneath a thin light horn-coloured periostraeum; sculpture of regular concentric striae, and towards the front margin of inconspicuous radial threads; margin of valves coarsely crenulated all round; hinge line with prominent teeth, three in front and five behind. Holotype: length 2.75 mm., height 3 mm., section 1.75 mm., Backstairs Passage, 32 fathoms, alive.

Australia: Beachport to 80 miles west of Eucla, 9-150 fathoms. S.W.A., S.A., Tas., Vict.