Shape ovate with convex medial face and concave lateral face. Dorsal depression grooved, fan-shaped. Dorsal margin and ventral margin approximately digitate, irregular. Sulcus ostial, deep. Ostium flared, oval and cauda elongate, tube-like, flexed ventrally at tip. Colliculum low. Pseudocolliculum above crista inferior. Crista superior and Crista inferior well-developed, poorly-developed at extremes. Neck dorso-ventrally constricted. Rostrum pointed, extended. Excisura wide. Notch shallow.