Shape ovate with convex medial face and concave lateral face. Dorsal depression grooved, above crista superior. dorsal margin and ventral margin approximately entire, lobed and serrate at posterior. Sulcus ostial, deep. Ostium flared, triangular and cauda tube-like, slightly bended ventrally at tip. Colliculum low, large in ostium. Crista superior ridge-like and crista inferior well-developed. Neck dorso-ventrally constricted. Rostrum blunt, large. Excisura large. Notch deep.