Part 30

CRYPTELLA. Webb. ([Greek: Kruptô], to conceal.) TESTACELLUS Ambiguus of Ferrusac. Published in Sowerby's Genera of Shells as PARMACELLA calyculata.--Descr. A small patelliform shell, with a very short papillary spire; and the aperture irregularly expanded. Fig. 256. Canary Islands.

CRYPTOCONCHUS. Bl. A genus composed of species of Chiton, the valves of which are covered by the integument, as Chiton porosus of Burrows. Ch. amiculatus of Pallas.

CRYPTODIBRANCHIATA. Bl. The first order of the class Cephalophora, Bl. containing families of molluscous animals destitute of shells.

CRYPTOSTOMA. Bl. Differs from SIGARETUS, Lam. principally in the soft parts of the animal. De Blainville remarks that he is acquainted with only two species (from the Indies), which he can with decision refer to the genus, but he thinks that many of the Lamarckian Sigareti may very probably be found to belong to it, as soon as the soft parts shall be known. The species which he figures is Cryptostoma Leachii. (Manuel de Malacologie, pl. 42. fig. 3.)

CTENOCONCHA. Gray. Described as having many characters in common with the Solens, the teeth like Nucula, but the cartilage entirely external. SOLENELLA, Sow.?

CUCULLÆA. Lam. (Cucullus, a hood.) Fam. Arcacea, Lam.--Descr. Sub-quadrate, nearly equivalve, sub-equilateral, deep; hinge rectilinear, with a series of angular teeth, small near the umbones, larger and more oblique towards the extremities; umbones separated by a flat external area, on which the ligament is spread. Anterior muscular impression produced into a sharp-edged plate or ledge, projecting from the side of the shell. Posterior muscular impression flat and indistinct.--Obs. This genus very much resembles Arca in general form, but differs in the oblique, lengthened character of the remote teeth, and in the singularly prominent edge of the muscular impression. China. Fig. 133, C. Auriculifera.

CUCUMIS. Klein. MARGINELLA, Auct.

CULTELLUS. Species of LUTRARIA, Lam. which have the umbones placed near the extremity of the shell. Ex. L. Solenoides, fig. 78.

CUMA. Humph. FUSUS and FASCIOLARIA, Lam.

CUMINGIA. Sow. Fam. Mactracea, Lam.--Descr. Equivalve, inequilateral, transverse, rounded anteriorly, subrostrated posteriorly. Hinge with a central spoon-shaped cavity in each valve, containing the cartilage; a very small anterior cardinal tooth in each valve; two lateral teeth in one valve, none in the other: muscular impressions two in each valve, distant; palleal impression with a very large posterior sinus.--Obs. The species known at present are found in sand, in the fissures of rocks in Tropical climates. They resemble Erycina in general form and character, but differ in having the internal cartilage placed in a prominent spoon-shaped process, while that of Erycina is contained in a hollow which sinks under the umbones. This genus should be placed near Amphidesma. Cumingia mutica, fig. 87.

CUNEIFORM. (Cuneus, a wedge.) Wedge-shaped, as Donax, fig. 108.

CUNEUS. Megerle. VENUS Meroe, Linn. and similar species.

CUNICULA. Sw. A sub-genus of Uniones, thus described:--"Ovate, oblong; bosses thick, but depressed; cardinal teeth moderate. C. planulata, patula, rubiginosa, secura, purpurascens."

CURVED. Arched or bent. Ex. Dentalium, fig. 2.

CURVULA. Rafinesque. A fossil imperfectly described as differing from Pinna, in being inequivalve.

CUVIERIA. Ranz. (Baron Cuvier.) Class, Pteropoda, Lam.--Descr. Thin, transparent, glassy, cylindrical, rounded and inflated at the closed extremity, compressed towards the opening, so as to render it oval. This genus differs from Vaginula in being rounded, instead of pointed, at the lower extremity. Mediterranean. Fig. 223, C. Columella.

CYCLAS. Brug. Fam. Conques Fluviatiles, Lam. Conchacea, Bl.--Descr. Orbicular, thin, subovate, ventricose, sub-equilateral, equivalve; cardinal teeth minute, one more or less complicated in the left valve, two diverging in the right; lateral teeth elongated, compressed, laminar, acute, doubled in the left valve; ligament external; epidermis thin, horny.--Obs. The Cyclades are viviparous, and abound in ditches, ponds, slow streams, &c. in Europe and North America. The genus Pisidium has been separated on account of a difference in the animal, and may be known from Cyclas by being less equilateral, and the anterior side being the longest. Fig. 111, C. Rivicola.

CYCLOBRANCHIATA. Bl. The third order of the second section of Paracephalophora Monoica, Bl. containing no genera of Testaceous Mollusca.

CYCLOCANTHA. Sw. A genus of "Trochidæ," consisting of Turbo stellaris and T. Calcar, and corresponding with the genus Calcar, Montf.

CYCLONASSA. Sw. A genus of "Nassinæ," Sw. consisting of Nassa Neritoidea, and corresponding with the genus Cyclops, Montf.

CYCLOPHORUS. Montf. A generic name proposed for those species of Cyclostoma, Auct. which have an umbilicus. C. Involvulus, fig. 304, would be the type of this genus.

CYCLOPS. Montf. NASSA Neritoidea, Auct. fig. 424.

CYCLOSTOMA. Auct. ([Greek: kuklos], cyclos, round; [Greek: stoma], stoma, mouth.) Fam. Colimacea, Lam. Cricostomata, Bl. A genus of land shells varying in shape from that of Pupa to that of a flat orb; the aperture is generally circular and the peritreme uninterrupted, thickened and sometimes reflected, the operculum is shelly and spiral. Two other genera of land shells are provided with opercula, and consequently might be confounded with this genus. In Helicina, the operculum is concentric and the peritreme is not continuous; while in the small genus hitherto almost unknown of Pupina, the peritreme is not continuous and there is a glassy enamel over the whole of the external surface. In the plates we have represented, C. ferrugineum, fig. 303; C. involvulus, fig. 304.

CYCLOTUS. Guild. A sub-genus of Cyclostoma, consisting of those species which are discoidal, as C. Planorbulum. Fig. 530.

CYLINDER. Montf. CONUS textile, Auct. (fig. 461) and other species having a cylindrical form.

CYLINDRELLA. Sw. A genus of the family "Ovulinæ," Sw. composed of cylindrical species of Ovulum? The wood-cut illustrating this genus has the appearance of a Bulla.

CYLINDRICAL. ([Greek: kulindros], a cylinder.) This like other mathematical terms is used with great latitude by Conchologists, and applied to any shell the sides of which are nearly parallel, with the extremities either rounded, flat, or conical. Ex. Oliva, fig. 457.

CYLLENE. Gray. Fam. Purpurifera, Lam.--Descr. Oval, thick, with a short acute spire; an oval aperture terminating anteriorly in a slight emargination, posteriorly in a short canal; a fold at the lower end of the body whorl; outer lip thick, striated within; angle of the whorls tuberculated.--Obs. This genus of small marine shells resembles Voluta in general character, but differs in having a smooth columella without folds. Recent, Pacific Ocean; Fosil, London clay. Fig. 425.