Shape oval with pointed dorsal angle in the middle of dorsal margin. Convex medial face and concave lateral face. Dorsal depression shallow. Dorsal margin and ventral margin slightly crenate. Sulcus ostial, deep. Ostium flared, triangular and cauda elongate, slightly flexed ventrally at posterior. Colliculum large in ostium, higher in cauda. Crista superior and crista inferior well-developed, both absent at posterior. Neck slightly constricted. Rostrum triangular, large. Excisura wide. Notch shallow.