History of British animals - University of Guam Marine Laboratory

444 MOLLUSCA. VENERID^. Cyprina.Brit. 114.—C. isl. Turt. Biv. Brit. 135.— Not uncommon on all partsof the coast.This is the largest British bivalve shell, measuring sometimes 13 inchesin circumference, and, exclusively of the animal, weighing upwards of 9ounces ; it is slightly truncated retrally ; the ligament at the beak is lodgedin a deep cavity ; there is no lunette in front of the beaks. At St Andrew'sit is called Daikie, and in Zetland Cuvie.511. C. triangularis.— Subtriangular, smooth, with a lengthenedcordiform depression in front of the beaks.Venus tri. Mont. Test. Brit. 577. t. xvii. f. 3—C. tri. Turt. Biv. Brit.136. t. xi. f. 19, 20.— South of England and Dublin bay.Diameter about half an inch ; yellowish-white ;strong, with a few obsoleteconcentric ridges;the beaks are produced, and the slope is nearly equal onboth sides ; in one valve two teeth, and a curved lateral one, in the otherthree teeth and a curved lateral one.512. C. minima. — Suborbicular, compressed, with broad,smooth, transverse ribs.Venus min. Mont. Test. Brit. 121. t. iii. f. 3—C. min. Turt. Biv. Brit.137—Southern coasts of England.Length a quarter of an inch, breadth rather more ; flesh-coloured, withtwo red spots near the beaks, and two near the margin, connected by twowhite lines ; glossy, strong. Dr Turton assigns to this species only twohinge teeth besides the lateral ones.EXTINCT SPECIES.1. C. aqualis Uniformly^convex, obcordate, or nearly circular, coveredwith numerous transverse concentric striae ; thick, particularly in the middle ;margin acute, extended, entire ; cicatrix obscure.— Venus equalis, Sower.Min. Conch, t. xxi.— In Crag.2. C. angulata.— Obtusely cordate, broader than long, beak short angular,rising on the posterior side, which is slightly truncated, smooth ;margin entire; larger hinge-teeth placed at an angle of about 60°.—Venus ang. Sower.Min. Conch, t. lxv.— In Green Sand.3. C. rustica Suborbicular, gibbose, smooth ; posterior side obscurely defined,convex, with a thick lateral tooth.—Venus rustica, Sower. Min. Conch.t. exevi.— In Crag.Gen. CXXVII. CYTHEREA.— Shell suborbicular or transverse,unequilateral ; hinge, on the right valve, of threedivergingteeth and one transverse and detached at theside under the lunule ; three diverging teeth in the othervalve, with an adjacent transverse cavity anteriorly;syphonmarks distinct.513. C. chionc.— Shell ovately-subtrigonal, smooth, glossy,with slight concentric lines of growth a lanceolate lunule raised;in the middle.