Shell small, thin, laterally much compressed, the sides parallel, anterior and posterior end raised, navicular, the summit anterior and considerably raised. Sculpture consisting of tine rather distant and indistinct radiate striae, crossed by distant concentric growthlines. Colour white. Nucleus minute, resting on the narrowly elevated summit, situate at the anterior two-fifths of the length. Anterior and posterior slope straight, side slopes lightly convex. Margin sharp, smooth. Interior white. Length, 5 mm. ; breadth, 2 mm. ; height, 2-8 mm. Type in the collection of Miss Mestayer, Wellington.