The shell is medium-sized, subtrigonal in outline, equivalve, and slightly inequilateral. The ligament is external and thick. The hinge has three strong cardinal teeth and one anterior and one posterior smooth lateral teeth in the left valve, against two in the right valve. The pallial sinus is inconspicuous, and the muscle scars are distinct. The exterior of the shell is chalky white under a deep brown periostracum, and the interior is chalky or porcelain-white.