Elongate, rounded, anteriorly, produced posteriorly; umbos at about the anterior third of length; about ten V-shaped teeth on the anterior side of the resilifer, and 15 imbricating teeth on the posterior side. A slightly curved anterior radial depression running from the umbo to the ventral margin leaves a very weakly marked sinuation on the anterior ventral margin of the shell. Length 18 mm., height 7 mm. Type locality: Port Kembla, New South Wales, 63-75 fathoms.