| 简要特征描述 |
Shell small, transverse and ventribiconvex with denticulate hinge line; maximum width at hinge line. Ventral valve hemipyramidal with a very high and flat, procline, tri−angular ventral nterarea. Delthyrium narrowly elongate triangular, at least apically covered by convex seudodeltidum. Dorsal valve gently convex, transverse triangular to trapezoidal in outline. Both valves medially licate, with three prominent round to medially grooved plications on orsal valve and three compound plications on ventral valve. Flanks enerally smooth. Ornament of growth lamellae only. Ventral nterior with dental ridges. A short median ridge may be present apically. Dorsal interior with well−developed ctenophoridium; rural plates or dorsal adminicula and median septum lacking. |
