Shell medium, elongate, narrowly triangular, flattened, strongly twisted posteriorly. Posterior as well as the anterior end, to some extent, pointed. Exterior distinctly sculptured by concentric fine ridges, becoming oblique posteriorly. Each valve with a spined ridge running from the beak to each dorsal extremity;flattened furrow below each posterior ridge (Oliver, 1975). Umbones near the middle of the dorsal side; ventral margin sharp, gently curved. Hinge with 2 cardinal teeth; well developed 1 lateral tooth on each side far away from the hinge. Colour: grey-white with bluish patches; interior bluish.