V. strigosa. V. aphrodina. V. Perronii. V. aphrodinoides. V. elegantina. V. flammea. V. rimularis. V. vulvina. V. vermiculosa. V. subrostrata. V. undulosa. V. pumila. V. ovata. V. inquinata. _V. Casina._ The Casina, or broad-ribbed Venus. Pl. 8, fig. 2. Sub-orbicular, with transversely acute recurved ridges; lamellar striæ; crenulated on the hind margin; slightly channelled behind the depression. _V. decussata._ The intersected Venus. Pl. 9, fig. 3. Species sub-rhomboidal, with decussated striæ; margin not denticulated; umbo placed near one end; the three teeth of the hinge very contiguous and very weak; exterior brownish and marked with purple lines. _V. aurea._ The golden Venus. Sub-orbicular, inequilateral, transversely and concentrically striated; yellow golden colour. _V. corbis._ The basket Venus. Species sub-rhomboidal, deeply latticed; teeth very thick, ligament entirely concealed, margin dentated. _V. puerpera._ The convex or spotted Venus. Species thick, solid, orbicular or sub-orbicular, with concentric striæ, or, rather, laminæ; teeth very thick; margin dentated. _V. granulata._ The granulated Venus. Species thick, solid, cardium-shaped, radiated from the summit to the base. 7. Venericardia. One species. This genus resembles the Venus, but has only two oblique cardinal teeth on each valve. Shell equivalve, inequilateral, sub-orbicular, sides generally with longitudinal rayed ribs; hinge with two oblique cardinal teeth in each valve, turned in the same direction. _V. imbricata._ The imbricated Venericardia. Pl. 9, fig. 1. Species almost round, having convex longitudinal ribs, covered with imbricated rough scales; inferior margin rounded and dentated; more and more equilateral; the two teeth short and oblique. FAMILY X. CARDIACEA. Five genera. 1. Cardium. Cockle, or Heart Shell. Forty-eight species. This genus received its name from its resemblance to a heart (καρδια). It is so well defined by Linnæus that no alteration was made by Lamarck, except in making two divisions of them; the first distinguished by having the anterior side as large or larger than the posterior, and no distinct angle at the apex; the second by possessing carinated or angular umbones, and the posterior side often much larger than the anterior. These shells are found at a small depth in the sand on almost every seashore.