Ovate with postero-dorsal angle and deep emarginated just below the angle, ventral portion v-shaped with point protrusion in the middle. Convex medial face and concave lateral face. Dorsal margin and ventral margin approximately entire. Sulcus ostial, deep. Ostium flared, oval and cauda elongate, flexed. Colliculum raised in ostium, oval. Crista superior well-developed. Crista inferior poorly-developed along ostium and well-developed along cauda. Neck ventrally constricted. Rostrum blunt. Excisura wide. Notch deep.