1. CYPRÆA. Lips thickened, inflected, with teeth; spire hidden, including _Cypræovulum_, _Luponia_, _Trivia_. Fig. 444 to 450. 2. OVULUM. Lips thickened, inflected, with slight crenulations; spire hidden. Fig. 440 to 443. 3. ERATO. Lips thickened, inflected; spire visible; a groove down the back. Fig. 454. 4. TEREBELLUM. Cylindrical, open at the anterior extremity; columella smooth; suture of the spire canaliculated. Fig. 451, 452. 5. OLIVA. Columella plaited, swelled into a varix at the anterior. Fig. 457, 458. 6. ANCILLARIA. The same, but the suture of the spire covered with enamel. Fig. 455, 456. 7. CONUS. Turbinated, numerous whorls; spire flat or short, conical; columella smooth. Fig 459 to 462. CONVOLUTE. (_Con_, together; _volvo_, to revolve). This term can be strictly applied only to symmetrical shells, signifying that the volutions are parallel to each other in a horizontal direction, as in the Ammonites, &c.; but the term is also commonly used in describing such shells as Conus, in which, the direction of the whorls being scarcely oblique, the last whorl almost entirely covers those which precede it. This is the case with Lamarck's family of Enroulées. Fig. 440 to 462. CORALLIOPHAGA. Bl. CYPRICARDIA Coralliophaga, Lam.--_Descr._ Oval, elongated, finely striated from the apex to the base, cylindrical, equivalve, very inequilateral; umbones slightly raised and quite anterior; hinge nearly the same in both valves; two small cardinal teeth, one of which is bifid, placed before a kind of lammellated tooth, beneath a very slender external ligament; two small, distant, muscular impressions, united by a striated palleal impression, which is strongly striated posteriorly.--_Obs._ This shell, which is found in the empty holes of dead Lithodomi, in some instances conforming its shape to its situation, differs from Cypricardia of Lamarck, principally in its cylindrical form. C. Carditoidea, fig. 92. Mediterranean and East Indies. CORBICULA. Megerle. CYRENA, Lam.