Mollusca from the great oolite, chiefly from Minchinhampton and the coast of Yorkshire. Part 3. Bivalves / Моллюски из большого оолита, главным образом из Минчинхэмптона и побережья Йоркшира. Часть 3. Двустворчатые

Testa subrhomboidea, fornicatd, concentrice lineata, umbonibus terminalibus incurvis, carina dorsali acuta, latere postico abrupto, lunula plana. (Goldfuss.)
Shell nearly rhomboidal or cordiform, elongated; unibones terminal, rather augulated and incurved; dorsal surface with an elevated acute angle; the lunule is very small and cordiform, its borders rounded; the anterior portion of the surface has concentric lines, which pass over the carina, and are soon lost upon the flattened posterior surface.The height, measured along the dorsal carina, very much exceeds the lateral diameter, the shell being much produced and pointed at the posterior and inferior extremity; it is associated with Opis lunulatus in the shelly beds of the Great Oolite, but is much less common; compared with that species it is much more lengthened and oblique, the lunule minute, and the lines are much more delicate and closely arranged.
Localities. Minchinhampton and Bisley Commons in the Great Oolite; Ancliff, Wiltshire; Ponton, Lincolnshire. Cloughton Wyke, Yorkshire. (Phillips.)