Elliptic in shape, tapering at posterior with convex medial face and concave lateral face. Dorsal margin and ventral margin entire. Sulcus ostial, shallow. Ostium flared and cauda tube-like directing ventrally. Crista superior and crista inferior poorly-developed. Neck slightly constricted. Rostrum short, blunt. Excisura wide. Notch very shallow.
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