Shell thick, moderately inflated with a variable, inequilateral shape, subtrigonal in outline. Umbones anterior, poorly inflated, pointing on top of dorsal margin which is strongly sloping on both sides and longest posteriorly. Anterior and ventral margins rounded, posterior end of shell bluntly angled. Lunule and escutcheon areas smoothish and poorly distinct. Posterodorsal slope shallowly convex, bordered by a low fold radiating toward posteroventral end of valves. Outer surface of shell with incised