Winged Chimney Clam

Shell size to 15 mm; shell thin, oval, inflated. Posterior extremity rounded. Antero-dorsal extremity widely open, gaping, higher than in Rocellaria stimpsoni. Umbo in anterior position, but not as anterior as in R. stimpsoni. Sculpture of commarginal cords. Most anterior part of valve represented by a wing-like projection of its ventral margin. Color translucent cream- to yellowish-white.