A Conchological Manual, George Brettingham Sowerby [little readers .TXT] 📗

See CORONAXIS, Swainson. The

   cones are mostly tropical, some are found as far north as the

   Mediterranean, and south as the Cape of Good Hope. The most beautiful

   species are from the East and West Indies.

 

   CONVOLUTÆ. (Enroulées, Lam.) A family of the 2nd section of the order

   Trachelipoda, Lam. the genera of which may be distinguished as

   follows:--

 

CYPRÆA. Lips thickened, inflected, with teeth; spire hidden,

       including _Cypræovulum_, _Luponia_, _Trivia_. Fig. 444 to 450.

 

OVULUM. Lips thickened, inflected, with slight crenulations;

       spire hidden. Fig. 440 to 443.

 

ERATO. Lips thickened, inflected; spire visible; a groove down

       the back. Fig. 454.

 

TEREBELLUM. Cylindrical, open at the anterior extremity;

       columella smooth; suture of the spire canaliculated. Fig. 451, 452.

 

OLIVA. Columella plaited, swelled into a varix at the anterior.

       Fig. 457, 458.

 

ANCILLARIA. The same, but the suture of the spire covered with

       enamel. Fig. 455, 456.

 

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.

 

   CORBIS. Cuv. (_A basket._) _Fam._ Nymphacea, Lam.--_Descr._ Transverse,

   oval, thick, ventricose, equivalve, sub-equilateral, free, cancellated,

   with denticulated internal margins; hinge with two cardinal and two

   lateral teeth in each valve; of the latter, one near and one remote

   from the umbones; muscular impressions lunulate, two in each valve,

   united by an entire palleal impression, without a sinus.--_Obs._ This

   genus, of which only two or three recent species are known, resembles

   many species of Venus and Cytherea in general form; but differs in

   having lateral teeth, and in the palleal impressions which in all the

   Veneres, &c. is sinuated. From Lucina it may be known, not only by its

   oval form, but also by the muscular impressions, which, in Lucina are

   produced into an elongated point; it will also be distinguished from

   Tellina, by the want of a posterior fold in the valve, for which that

   genus is remarkable. C. Fimbriata, fig. 101, is an inhabitant of the

   Indian Ocean. Several fossil species are found in the recent

   formations, above the chalk, at Grignon and Hauteville.

 

   CORBULA. Brug. (_A little basket._) _Fam._ Corbulacea, Lam. Conchacea,

   Bl.--_Descr._ Inequivalve, sub-equilateral, transverse, gibbose, not

   gaping; cardinal tooth in each valve, conical, curved, prominent,

   inserting its extremity into a pit in the opposite hinge; cartilage

   attached to the tooth of the smaller valve, and the pit in the larger;

   muscular impressions, two in each valve, distant, rather irregular;

   palleal impression posteriorly angulated.--_Obs._ The shells composing

   this genus were placed in Mya by Linnæus, but differ from the true Myæ

   in having a sinus in the palleal impression, and a prominent

   ligamentiferous tooth in each valve, whereas the Myæ have but one. The

   Corbulæ are marine, some species inhabiting the British coasts. Fossil

   species occur abundantly in green sand, London clay, crag, and

   corresponding formations. Fig. 89. C. Nucleus.

 

   CORBULACEA. (Corbulées, Lam.) A family of the order Conchifera

   Dimyaria, Lam., containing the genera--

 

CORBULA, with a prominent curved tooth. The Fresh-water species

       has been separated under the name _Potamomya_. Fig. 89.

 

PANDORA. Thin, pearly, no teeth. Fig. 90.

 

   CORDIFORM. (_Cor_, a heart.) Heart-shaped, a term applied generally to

   any shell which may be fancied to resemble a heart in shape, as

   Isocardia, fig. 126, and Cardium Dionæum, fig. 122.

 

 CORIACEOUS. (_Corium_, leather.) Of the substance of leather. _Ex._,

   the integument into which the valves of Chitones are inserted.

 

   CORIOCELLA. Bl. The animal designated by this name is described by De

   Blainville as being without any traces of shell, either internal or

   external. This must have arisen from the imperfection of the specimen

   described, probably deprived by accident of its shell. The testaceous

   appendage of the Coriocella is now well known to naturalists. It is a

   milky white, transparent shell, shaped like Sigaretus.

 

   CORNEA, and PISUM, Megerle. CYCLAS, Lam.

 

   CORNEO-CALCAREOUS. A term used to express the mixture of horny and

   shelly matter which enters into the composition of some shells,

   Aplysia, for instance. It is also applied to those Opercula, which are

   horny on one side, and testaceous on the other, as that of Turbo.

 

   CORNEUS. Horny. A species of Patella has had the specific name corneus

   given to it, because its texture more nearly resembles that of a horn

   than that of a shell. The epidermis of fresh-water shells is of a

   similar composition.

 

   CORNUCOPIA. Humph. LEPAS, Linn.

 

   CORONALES. See CORONULAR MULTIVALVES.

 

   CORONATED. (_Corona_, a crown.) Applied to shells when ornamented with

   a series of points, tubercles, &c., round the upper edges of the

   volutions. _Ex._ Conus Nocturnus, fig. 459.

 

   CORONAXIS. One of the two genera into which Swainson divides the genus

   Conus, consisting of those species which have a row of tubercles on the

   upper edge of the whorls, an arrangement by which he would in many

   instances, not only separate between two individuals of the same

   species, but also between two parts of the same shell; for instances

   occur in which the earlier whorls are coronated, while the body whorl

   and the penultimate are perfectly plain.

 

   CORONULA. (_Corona_, a crown, dim.) _Order_, Sessile Cirripedes, Lam.

   _Fam._ Balanidea, Bl.--_Descr._ Six radiated valves, joined side by

   side in a circle, forming a depressed cone; internal structure of the

   valves, porous or chambered; thickened at the base; operculum

   consisting of four valves in pairs; imbedded horizontally in a

   cartilaginous substance.--_Obs._ The shells composing this genus are

   found partly imbedded in the skin of whales, and the shells of

   tortoises, and are therefore destitute of the shelly foundation on

   which the Balani and other Coronular Multivalves are supported. C.

   Testudinaria, (CHELONOBIA, Leach,) fig. 15. C. Balænarum, (CETOPIRUS,

   Ranz.) fig. 16. C. Diadema, (DIADEMA, Ranz.) fig. 17.

 

   CORONULAR MULTIVALVES are those which have their parietal valves joined

   together side by side in a circle, surrounding the body of the animal,

   so as to form a sort of coronet. This is the characteristic of the

   Sessile Cirripedes of Lamarck's system, the Balanidea of De Blainville.

 

   CORRODED. (_Corrodo_, eat away, consume.) The umbones, apices, and

   other thick parts of shells, are frequently worn away or consumed by

   the action of the element in which they exist. As the thickest parts of

   some shells are the most subject to this operation, it appears to the

   author to arise from the outer surface of the shell, being less under

   the influence of the animal juices than the other parts; and therefore,

   more exposed to the influence of the surrounding element. This,

   however, is not the case with respect to the Nayades and other

   fresh-water shells; with these, corrosion does not take place until

   after the thick epidermis which covers them, becomes wounded by some

   means or other, and then the animal thickens its shell within as fast

   as it is corroded without.

 

   CORTALUS. Montf. (Conch. Syst. 1. 115.) A genus of microscopic

   Foraminifera, placed by De Blainville in a division of the genus

   Rotalites.

 

   COSTATED. Ribbed, as Cardium Angulatum, fig. 123.

 

   COSTELLARIA. A sub-genus of the genus Tiara, Sw. (Mitra.) C. rigida.

   Swainson, Zool. Ill. 1st series, pl. 29.

 

   COWRY. A common name for shells of the genus Cypræa.

 

   CRANIA. (_Cranium_, a skull.) _Fam._ Rudistes, Lam. _Order_,

   Pallio-branchiata, Bl.--_Descr._ Inequivalve, equilateral, irregular,

   sub-quadrate; upper valve patelliform, conical, with the umbo near the

   centre; lower valve attached by its outer surface; muscular

   impressions, 4 in each valve; two large, posterior, distant; two small,

   near to each other, central. No hinge teeth; no ligament.--_Obs._ This

   genus properly belongs to the Brachiopoda, Lam. It differs from

   Orbicula in the mode of attachment, which in the latter, is by a byssus

   passing through the lower valve, and not by the valve itself. Hipponyx

   has only two muscular impressions in each valve. The name of this genus

   is derived from the inner surface of the attached valve, which presents

   a remarkable resemblance to the facial portion of a human skull. This

   appearance is caused by the situation and elevated edges of the

   muscular impressions. Fig. 197. Coasts of Britain and Mediterranean.

 

   CRASSATED. (_Crassus_, thick.) Used to express a thickness in the

   substance of a shell. _Ex._ Glycimeris, fig. 67.

 

   CRASSATELLA. Lam. (_Crassus_, thick.) _Fam._ Mactracea, Lam. Conchacea,

   Bl.--_Descr._ Equivalve, inequilateral, close, thick, rounded

   anteriorly, rostrated posteriorly, with denticulated margins, smooth,

   or ribbed transversely; hinge with a triangular pit containing the

   cartilage, two anterior cardinal teeth, and a posterior depression in

   one valve; one anterior tooth and a slight anterior marginal elevation,

   and a posterior elevation in the other valve. Muscular impressions

   distant, strongly marked. Palleal impression not sinuated.--_Obs._ The

   few recent species known are marine, several being brought from the

   coasts of New Holland. Fossil species are found in Calcaire-grossier

   and London clay. The Crassatella are known from the Veneres, &c., by

   the ligamentary pit in the hinge, and from Lutraria and Mactra by the

   thickness and closeness of the shell. Fig. 84, C. rostrata.

 

   CRASSINA. Lam. ASTARTE, Sow.

 

   CRASSIPEDES. Lam. (_Crassus_, thick; _pes_, foot.) The first section of

   the order Conchifera Dimyaria, Lam. In this section the foot of the

   animal is thick, and the shell gapes considerably. It is divided into

   the families Tubicolæ, Pholadidæ, Solenidæ, and Myaria. Fig. 44 to 76.

 

   CRASSISPIRA. Sw. A genus separated from COLUMBELLA, Auct. for which Mr.

   Swainson quotes "Pleurotoma Bottæ, Auct." Crassispira fasciata, Sw.

   Lardn. Cyclop. Malac. p. 313.

 

   CRENATED. (_Crena_, a notch.) Applied to small notches, not

   sufficiently raised or defined, to be compared to teeth. _Ex._ The

   hinge of Iridina, fig. 150.

 

   CRENATULA. Lam. _Fam._ Malleacea, Lam. Margaritacea, Bl.--_Descr._

   Compressed, foliated, irregular, sub-equivalve, inequilateral, oblique;

   umbones terminal; hinge linear, nearly straight, with a series of

   excavations, containing the cartilage, while the intervening ridges are

   covered with the ligament, properly so called. Muscular impression

   oblong, indistinct.--_Obs._ This genus is known from Perna by the

   hinge, which in the latter is composed of a series of regular,

   straight, ligamentary grooves placed across it. In Crenatula also there

   is no passage for the byssus, as in Perna. C. Mytiloides, fig. 168.

   Coasts of the Red Sea.

 

   CRENULATED. Finely crenated or notched.

 

   CREPIDULA. Lam. (_Crepidula_, a little slipper.) _Fam._ Calyptracea,

   Lam. and Bl.--_Descr._ Oval, irregular, patelliform; apex lateral,

   incurved, or sub-spiral; external surface convex, smooth, ribbed,

   waved, or covered with spines; interior concave, smooth, with a

   flattish septum reaching nearly half across the cavity; epidermis light

   brown.--_Obs._ The difference between this genus and Calyptræa is that

   in the latter, the septum is more free from the sides of the shell, so

   that, instead of forming a regular plate, covering half the aperture,

   it assumes a variety of shapes, and in some is cup-shaped, in others

   forked, and in some forms a little angular shelf. Indeed, the

   variations are so numerous that I think it would be better to throw the

   two genera into one, and then divide them into smaller groups. Some

   species of Calyptræa are farther removed from each other with respect

   to the characters of the septum and general form of the shell, than

   they are from the Crepidulæ. Fig. 239. Mediterranean, North and South