. Oblong, almost equilateral, thin, semi-transparent, surface slightly rough, colour dull white; posterior side gaping, broadly rounded, with a furrow obliquely from the umbo to postero-ventral margin; anterior side rounded; umbos slightly prominent, fissured; resilifer spoon-like, projecting from the hinge line, reinforced by a shining white clavicle or buttress in each valve; sculpture of many feeble concentric lirae. Length 44 mm., height 21 mm., section 14 mm. Type locality: Port Phillip.