CLEIDOTHÆRUS. Hutch. ([Greek: Thairos], hinge, [Greek: Kleis], clavicle.) _Fam._ Chamaceæ or Myariæ, Lam.--_Descr._ Inequivalve, irregular, solid, attached; with one cardinal, conical tooth in the free valve, entering a corresponding indenture in the other; and an oblong shelly appendage, fixed by an internal cartilage in a groove under the umbones; muscular impressions, two in each valve, one elongated, the other uniform.--_Obs._ This shell is like Chama in general form, but is distinguished by the clavicle or shelly appendage from which its name is derived. Fig. 75. New South Wales. CLEODORA. _Per. et Les. Fam._ Pteropoda, Lam. Thecosomata, Bl.--_Descr._ Thin, transparent, pyramidal, with flat alate sides, and oval aperture. Fig. 221, C. cuspidata. CLISIPHONITES. Montf. Microscopic. LENTICULINA, Bl. CLITHON. Montf. NERITINA Corona, spinosa, &c. Auct. fig. 325. CLITIA. Leach. _Fam._ Balanidea, Bl. _Order_, Sessile Cirripedes, Lam.--_Descr._ Sub-conical, compressed, consisting of four unequal valves, two larger and two smaller, joined together side by side, by the interlocking of their dentated edges, a process somewhat like that which joiners call dove-tailing. Operculum, consisting of two unequal pointed valves.--_Obs._ Clitia is known from Creusia, by the articulations of the valves, and by the operculum, which in Creusia consists of four valves. Fig. 20. C. Verruca, (Lepas Verruca, Gmelin.) Britain and Peru. CLOSE. The margins of a bivalve shell are described as being close, when there is no hiatus between them in any part, otherwise they are described as _gaping_. CLOTHO. Faujas. _Fam._ Conchacea, Bl. More properly belonging to the Pyloridea, Bl.; and the Lithophagidæ, Lam.--_Descr._ "Oval, nearly regular, longitudinally striated, equivalve, sub-equilateral; hinge consisting of a bifid tooth, curved like a crochet, larger in one valve than in the other." This description is translated from Blainville, who states that he has never seen the shell. Annales du Museum D'Histoire Naturelle, tom. 9, pl. 17, fig. 4-6. CLYPEIFORM. (_Clypeus_, a shield.) Open, flat, shaped like a shield or buckler, as Umbrella, fig. 233, and Parmophorus, fig. 242. CLYPIDELLA. Sw. A sub-genus of Fissurella, described as having one extremity of the shell slightly raised. C. pustula. Sow. Gen. fig. 3. COAT OF MAIL. A common name given to shells of the genus Chiton, on account of their resemblance to jointed armour. COBRESIA. Hübner. VITRINA, Auct. COCHLIATE. (_Cochleare_, a spoon). Applied to any shell or part which is hollow and oval, as Patellæ, &c. The cavity containing the cartilage in Mya, fig. 71, is Cochleate.