CLAVA. Humph. CERITHIUM, Lam. CLAVAGELLA. Lam. (_Clava_, a club.) _Fam._ Tubicolæ, Lam. Pyloridea, Bl.--_Descr._ Two irregular flattish valves, one fixed or soldered, so as to form part of the side of an irregular shelly tube; the other free within the tube near the base.--_Obs._ The shells composing this genus are found in stones, madrepores, &c. and appear to form the connecting link between Aspergillum, which has both valves cemented into the tube; and Fistulana, in which both are free. Fig. 45, a fossil Clavagella. Found recent on the Coast of Malta and New South Wales. CLAVALITHES. Sw. A genus composed of some fossil shells, separated from the genus Fusus, which, having the general form of Turbinella Rapa, &c. are considered by Swainson, as holding an intermediate station between Fusus and the Turbinellidæ.--_Descr._ "Unequally sub-fusiform; the body whorl, and spire, being conic; and the canal suddenly contracted and attenuated; terminal whorls papillary; inner lip thick; pillar smooth, C. longævus, clavellatus, Noæ, ponderosus, Sw."--_Obs._ The papillary spire may form a sufficient reason for separating this genus from Fusus, while the absence of plates on the columella places them at a still greater distance from Turbinella. CLAVATE. When one extremity of the shell is attenuated, and the other becomes suddenly ventricose or globular, it is said to be Clavate. _Ex._ Murex Haustellum, fig. 396. CLAVATULA. Lam. The generic name by which Lamarck originally distinguished those species of Pleurotoma which were remarkable for the shortness of their canals. In his system, however, they are re-united to Pleurotoma. Fig. 381, P. Strombiformis. CLAVICANTHA. Sw. A genus separated from Pleurotoma, Lam. consisting of species, which are described as "thick, sub-fusiform; the surface rugose, and the whorls sub-coronated; channel short; slit assuming the form of a short, broad sinus. C. imperialis, E. M. 440, spirata, E. M. 440, fig. 5, conica, E. M. 439, fig. 9, echinata, E. M. 439, fig. 8, Auriculifera, E. M. 439, fig. 10." CLAVICLE. (_clavis_, a key.) A little key. This term is applied to the bony appendage in the hinge of some species of Anatina, (those included in the generic term Lyonsia) Cleidothærus, Myochama, &c. CLAVULINA. D'Orb. A genus of microscopic Foraminifera. CLAVUS. Montf. A genus of microscopic Foraminifera.