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Show 412 MOLJ ... USCA. tion of the edges of the mantle previous to its uniting with the impression of the posterior transverse muscle(!). CARDIUM, Lin. The Cardia, like many other bivalves, have an equivalve, convex shell, with salient summits curved towards the hinge, which, when viewing it sidewise, gives it the figure of a heart; hence its name of Ca1·dium, heart, &c. Ribs, more or less elevated, are regularly distributed from the summits to the edges of the valves; but what chiefly distinguishes the Cardia, is the hinge, through which, in the middle, are two small te eth, and at some distance before and behind a projecting tooth or plate. The animal,-CERASTEs, Poli,-has generally an ample aperture in the mantle, a very large foot forming an elbow in the middle and with its point directed forwards, and two short or but moderately long tubes. Numerous species of Cardia are found . on the coast of France, some of which are eaten, such as the C. edule, L.; Chemn., VI, xix, 194. Fawn-coloured or whitish, with twenty-six transversely plicated ribs. Under the name of HEMIOARDIUM, we might separate those spe· cies in which the valves are compressed from before backwards, and strongly carinated in the middle; for it seems almost certain, that a modification of the animal must be a necessary consequence of this singular configuration(2). DoNAX, Lin. The Donaces have nearly the same kind of hinge as the Cardia, but their shell is of a ve1·y different form, being a triangle, of which the obtuse angle is at the summit of the valves, and the base at their edge, and of which the shortest side is that of the ligament, or the posterior side, a rare circumstance in this degree, among bi· valves. They arc generally small, and prettily striated from the summits to the edges; their animal-PERONlEA, Poli, is furnished ( 1) They form the family of the CoNcnACEA, Blainv. (2) Cardium cardissa, VI, xiv, 143-146;-Card. rosewm, lb., 147;-Card. 171071- strosum, lb. 149, 150;-Card. hemicardium, Id., xi, 159-161. The other Cardia of Gmelin may remain where they are, the C. gaditanum ex· cepted, which is a Pectunculus. There are several fossil species de~cribed by Messrs Lamarck, Brocchi, and Brongniart. ACEPHALA TEST ACEA. 413 with long tubes which are received into a sinus of the mantle. Some of them are found on the coast of France( 1 ). The CvcLAs, Brug. Separated from Venus by Brugiere, like the Cardia and Donaces, has two teeth in the middle of the hinge, and before and behind, two salient, and sometimes crenulated plates; but the shell, as in several species of Venus, is more or less rounded, equilateral, and transveJ ·sely striated. The animal has moderate tubes. The external tint is usually grey or greenish. The Cyclades inhabit fresh water. One species, the Tellina cornea, L.; Chemn., VI, xiii, 1 S3, is very common on the coast of France(2). M. Lamarck separates the CYllENA, Lam. Where the shell is thick, slightly triangular and oblique, covered with an epidermis, and otherwise distinguished from the Cyclades by having three cardinal teeth. The Cyrenre also inhabit rivers, but there are none in France(3). CYPRINA, Lam. Also separated f1·om the Cyclades by Lamarck; the s\ell is thick, oval, with recurved summits, and three stout teeth; f\'rther back is (1) Donaxrugosa, Chemn., VI, xxv, 250-252;-D. trunulus, lb., xxvi, 253, 254;-D. striata, Knorr., DeJic., VI, xxviii, 8;-D. dentie1•ata, Chemn., I, c, 256, 257;-D. faba, Ib., 266;-D. spinosa, lb., 258. Fossi'species are numerous in the environs of Paris. See Lamarck, Ann. du Mus, VIII, 139, and Deshayes, Coq. foss. des Env. de Paris, I, pl. xvii, xviii. The Donax irregularis, from the Environs of D:o described by M. Bastorat in the Mcm. de Ia Soc. d'Hist. Nat. de Paris, t. II, pl iv, f. 19, A, B, is the type of a new genus lately established-Bullet. de la So· Lin. de Bourdeaux, II, by M. Charles Desmoulins, under the name of GnATFUl'lA. It is distinguished from the Donaces by the presence of several dentiforrlamella: which accompany the cardinal teeth. Several species of Venus, and some Mal'm, are mixed with these true Donaces byGmclin. (2) Add Tellina rivalis, Mull., Drap X, 4, 5;--Cyclas jontinalis, Drap., lb., 8-12;-Cycl. caliculata, lb., 13, 14;-l'ellina lacustris, Gm., Chemu., XTII, 135; -Te/J. amnica, lb., 134·-Tell. jl1iatilis,- Tell. jluminalis, Chemn. VI xxx 320. , ' ' ' C (3) Tell. jl~minea, Chemn., 1~ 322, 323;-Venus coa:xans, Id., xxxii, 336, or yrena ceylantca, Lam., ,E.ncyc ,lethod., pen., pl. 302, f. 4;-Venus borealis, Id., ~II, xuix, 312, 314;-Cycltu!Jrdiniana, Bose., Shells., III, xviii, 4. Fossil speCies abound near Paris. sccJeshayes, Coq. Foss., 1, pl. 18, 19. |
