A Conchological Manual by George Brettingham Sowerby (best interesting books to read txt) 📕

inner edge of the aperture, including that part of it which covers

   the body whorl, is called the columellar lip. In fig. 431, the anterior

   termination of the columella is indicated by the letter c. The axis, is

   an imaginary line drawn strictly through the centre of the whorls,

   whether their inner edges form a solid column or not.

 

   COLUMELLAR LIP. The inner lip. See COLUMELLA.

 

   COLUMELLATA. Lam. A family of the order Trachelipoda, Lam. containing

   the following genera:--

 

MITRA. Elongated; aperture narrow; strong folds on the

       columella; including _Mitrella_, _Mitreola_, _Tiara_, and

       _Conohelix_. Fig. 431, 432.

 

MARGINELLA. Outer lip reflected; including _Volutella_,

       _Persicula_, _Gibberula_, and _Glabella_. Fig. 437.

 

COLUMBELLA. Outer and inner lips denticulated or granulated.

       Fig. 430.

 

VOLUTA. Outer lip thickened; folds on the columella; aperture

       generally wide; apex papillary; including _Scaphella_, _Harpula_,

       _Volutilithes_, _Cymbiola_. Fig. 433, 436.

 

MELO. Shell comparatively light; spire short, sometimes hidden;

       apex round, spiral; folds on the columella laminar. Fig. 435.

 

CYMBA. Upper edge of the aperture separated from the body whorl

       by a flat disc; apex mammillated, irregular; folds on the

       columella. Fig. 434.

 

VOLVARIA. Cylindrical; aperture long, narrow; folds on the

       columella; spire hidden. Fig. 439.

 

   COLUS. Humphrey. FUSUS, Lam.

 

   COMPLANARIA. Sw. A subgenus of ALASMODON (Unio), thus described, "shell

   winged; the valves connate; the bosses very small and depressed;

   cardinal teeth two or three; lateral teeth represented by irregular

   grooves. C. gigas (Unio), Sow. Man. fig. 141. Alasmodon complanatus,

   Say. C. rugosa, Sw."

 

   COMPRESSED. Pressed together, or flattened. The application is the same

   as in common use. A Patella may be described as a vertically compressed

   cone. A Ranella, on account of the two rows of varices skirting the

   whorls, appears, as it were, laterally compressed. A bivalve shell is

   said to be compressed when it is flat, that is, when but a small cavity

   is left in the deepest part when the valves are closed. Perhaps the

   Placuna placenta, fig. 184, is the most remarkable instance of this.

 

   CONCAMERATIONS. (_Con_, with, _camera_, a chamber.) A series of

   Chambers joining each other, as in Nautilus, Spirula, &c.

 

   CONCENTRIC. A term applied to the direction taken by the lines of

   growth in spiral and other shells, (_longitudinal_ of some authors.)

   Every fresh layer of shelly matter forms a new circle round an

   imaginary line, drawn through the centre of the spiral cone, down from

   the nucleus. When the edges of the successive layers are marked by any

   external characters, the shell is said to be concentrically striated,

   banded, grooved, costated, &c. A fine illustration of the latter is to

   be seen in the Scalaria or Wentletrap, fig. 351, Lines, bands, ribs,

   &c. in the opposite direction, (_transverse_ of some authors,) are

   "radiating" in bivalves, as the ribs of Cardium, fig. 123, and "spiral"

   in univalves, that is, following the direction of the whorls, as the

   bands of colour in Pyramidella, fig. 342.

 

   CONCHACEA. Bl. The eighth family of the order Lamellibranchiata, Bl.

   The shells are described as follows: nearly always regular, valves

   closed all round; apices curved towards the anterior; dorsal hinge

   complete, with teeth and ligament; the latter external or internal,

   short and thick; two distinct muscular impressions, united at the lower

   part by a parallel impression, which is frequently sinuated at the

   posterior. The genera described in this family are divided into three

   sections. First, those which are regular, and have distant lateral

   teeth, Cardium, Donax, Tellina, Lucina, Cyclas, Cyprina, Mactra, and

   Erycina. Second, those which are regular, and have no distant lateral

   teeth, Crassatella and Venus. Third, those which are irregular,

   Venerupis, Coralliophaga, Clotho, Corbula, Sphænia, and Ungulina.

 

   CONCHACEA. Lam. A family of Lamarck's order Conchifera Dimyaria.

   Regular, unattached in general, closed at the sides. They are always

   more or less inequilateral. The _Marine_ Conchacea are those which

   inhabit the sea. The fluviatile Conchacea are those which are found in

   rivers, ponds, &c. Each of these contain various genera, which may be

   arranged as follows:--

 

   _Fluviatile._

 

CYRENELLA. Three cardinal teeth; ligament long; shell thin. Fig.

       114.

 

CYCLAS. Thin, oval; cardinal and lateral teeth; anterior side

       shortest, including _Pera_.

 

PISIDIUM. The same, with the posterior side shortest. Fig. 112.

 

CYRENA. Thick; cardinal and lateral teeth. Fig. 113.

 

POTAMOPHILA. Two thick cardinal teeth. Fig 115.

 

   _Marine._

 

CYPRINA. Two cardinal teeth, and one remote lateral tooth. Fig.

       116.

 

VENUS. Three cardinal, no lateral teeth; including _Artemis_.

       Fig. 118, 119, 119a.

 

CYTHEREA. Several cardinal teeth; one very short lateral tooth.

       Fig. 117, 117_a_, 117_b_, 117_c_, 117d.

 

PULLASTRA. Cardinal teeth notched, otherwise like Venus. Fig.

       120.

 

ASTARTE. Three cardinal teeth; ligament short. Fig. 110.

 

           VENERICARDIA belongs to the Cardiacea.

 

   CONCHIFERA. Lam. The 11th class of Invertebrata, consisting of all

   those animals which have bivalve shells. Lamarck divides the class into

   Dimyaria, which have two adductor muscles; and Monomyaria, which have

   but one.

 

   CONCHOLEPAS. Montf. (CONCHA, a shell; lepas, a stone or rock.) _Fam._

   Purpurifera, Lam. Entomostomata, Bl.--_Descr._ Oval, imbricated, thick;

   with a very short spire and large oval patelliform aperture,

   terminating anteriorly in a slight emargination; outer lip crenated,

   with two produced points or teeth towards the anterior, inner lip

   smooth, nearly flat, reflected over the last whorl, so as nearly or

   entirely to cover it; operculum horny. Marine, only one species known,

   from Peru.--_Obs._ This shell is placed near Patella by Lamarck, on

   account of its large open aperture; but having a horny operculum, and

   resembling Purpurea in other respects. Fig. 418. Concholepas Peruviana.

 

   CONCHOTRYA. Gray. (_Concha_, a shell; [Greek: Truo], (_tryo_) to bore.)

   _Order_, Pedunculated Cirripedes, Lam.--_Descr._ Five pieces, two pairs

   ventral, one single; shaped like Pentelasmis. Found in holes.

 

   CONCHYLIOMORPHITE. A term used by De Blainville to designate the cast

   or model of a fossil shell, formed by a siliceous substance which has

   entered or surrounded it when in a liquid state, and subsequently

   become hardened into flint. The shell has afterwards decomposed or

   fallen off by accident, leaving its external or internal characters to

   be conjectured from the monumental impressions that remain.

 

   CONCHYTA. Hupsch Mus. CALCEOLA, Lam.

 

   CONE. A common name for shells of the genus Conus.

 

   CONE. This mathematical term is used by conchologists in its utmost

   latitude of signification to express a body, which in its formation,

   commences in a small point, called the apex, and increases in width

   towards the conclusion or base. It is applied to all shells, whether

   the increase in width be gradual or sudden; or whether in its growth,

   it takes a straight, oblique, curved, or spirally-twisted course. In

   this sense, a bivalve would be described as a pair of rapidly

   enlarging, oblique cones, and the aperture of every spiral shell would

   be its base. But this phraseology being in disuse, it is only mentioned

   here that it may be understood when occasionally met with.

 

   CONELLA. Sw. A genus composed of species of the genus Columbella, Lam.

   which have a conical form, and which, on that account, are considered

   by Swainson as belonging to his family of Coninæ. Swains. Lardner.

   Cyclop. Malac. described at p. 312. C. picata, Sw. fig. 17, a. p. 151.

 

   CONFLUENT. A term applied to two parts of a shell when they gradually

   flow into each other, as, for instance, the inner and outer lips of

   Univalves when they pass into each other at the anterior extremity,

   without the intervention of a notch or angle.

 

   CONIA. Leach. _Fam._ Balanidea. _Order_, Sessile Cirripedes,

   Lam.--_Descr._ Four rather irregular valves, of porous structure,

   placed side by side, so as to form a circular cone, supported at the

   base on a shelly plate, and closed at the aperture by an operculum

   consisting of four valves in pairs. Distinguished from Creusia by its

   porous structure and by its flat support; that of Creusia being

   cup-shaped. Fig. 21, Conia porosa.

 

   CONICAL. A term applied in the ordinary sense, and not as explained

   above, under the word CONE.

 

   CONIDEA. Sw. A genus separated from Columbella, Lam. thus described,

   "Mitra shaped, fusiform; spire equal or longer than the aperture; the

   whorls tumid; outer lip slightly gibbous above, contracted below;

   margin not inflected; striated within; inner lip terminating in an

   elevated ridge, but with the teeth obsolete. C. semipunctata,

   (_Columbella_, Lam.) Mart. 44. fig. 465, 466." Africa.

 

   CONILITES. _Fam._ Orthocerata, Lam. & Bl.--_Descr._ "Conical, straight

   or slightly curved; having a thin external covering, independent of the

   nut or alveole, which it contains. Alveole transversely chambered,

   sub-separable." (Translated from Lam.)--_Obs._ The difference between

   Belemnites and Conilites is that the external sheath of the latter is

   thin, and not filled up with solid matter, from the point of the

   alveole to the apex, as in the former. De Blainville places in this

   genus the genera Thalamulus, Achelois and Antimomus, Montf. two of

   which are figured, Knor. Sup. Fab. iv. fig. 1. 1. 8. 9. Conilites

   Pyramidatus, fig. 470.

 

   CONILITHES. Sw. A sub-genus of Coronaxis, Sw. (Coni, with coronated

   whorls) thus described, "Conic; spire considerably elevated; the

   aperture linear, C. antediluvianus, Sow. Gen. f. 1."

 

   CONOHELIX. Sw. (_Conus and Helix._) The generic name given to those

   species of Mitra which are conical in form. Fig. 432, C. marmorata.

 

   CONOPLÆA. Say. _Order_, Sessile Cirripedes, Lam. A genus composed of

   Balani, attached to the stems of Gorgonia, having their bases

   elongated. _Ex._ fig. 27, Balanus Galeatus.

 

   CONORBIS. Sw. A genus composed of species of CONUS, such as C.

   dormitor, (Sowerby, gen. fig. 8) which have elevated spires and the

   upper part of the outer lip deeply sinuated. Mr. Swainson considers

   these fossil species as analogous to the Pleurotomæ. _Sw._ Lard.

   Cyclop. Malac. p. 312.

 

   CONOVULUM. A genus proposed by Lamarck, to include the small, conical

   species of Auricula, which have the outer lip simple. This genus was

   afterwards abandoned by the author. _Ex._ fig. 298, Auricula

   coniformis.

 

   CONTIGUOUS. (_Contingo_, to touch.) A term applied to the whorls of

   spiral shells when they rest upon, or touch each other. This is the

   case in a great majority of instances. When, on the contrary, there is

   a space between the whorls, they are said to be non-contiguous,

   detached, or free. Examples of non-contiguous whorls are to be seen in

   Scalaria, fig. 351 (in this case, the distance between the whorls is

   small), and in Crioceratites, fig. 482. A "_Columella contiguous to the

   axis_," is when in the centre of the shell and takes the place of the

   imaginary line which forms its axis.

 

   CONTINUOUS. Carried on without interruption, as the siphon in Spirula,

   the varices in Ranella, fig. 394, which, occurring in a corresponding

   part of each whorl, form a continuous ridge.

 

   CONULARIA. Miller. A genus of Orthocerata, described as conical,

   straight, or nearly so, divided into chambers by imperforate septa;

   aperture half closed; apex solid, obtuse; external surface finely

   striated. Resembling Orthoceras, but wanting the siphon. Fig. 449.

 

   CONUS. Auct. ([Greek: Kônos], a cone.) _Fam._ Enroulées, Lam.

   Angyostomata, Bl.--_Descr._ Conical, convolute, with a short spire,

   consisting of numerous whorls; and narrow lengthened aperture,

   terminating in a slight emargination at each extremity; outer lip thin;

   epidermis thin; operculum small, pointed, horny.--_Obs._ This

   well-known genus of shells is easily distinguished from any other, by

   its conical form, its smooth columella, its narrow aperture, and thin

   outer lip. The form of the spire varies from flat and even partially

   concave, to a regular pyramidal cone; and the upper edges of the whorls

   are rounded in some species, angulated in others, and in some are waved

   or coronated. The variety of marking and the numerous delicate tints of

   these shells have caused them to be highly appreciated by amateur

   collectors; and many species, as the C. Ammiralis, or admiral; the C.

   Gloria Maris, or Glory of the Sea; the C. Cedonulli ("I yield to

   none"), and others, have always produced good prices in the markets. We

   give figures of the principal forms, as expressed in the genera

   proposed by De Montfort, of Rhombus, Hermes, Rollus and Cylinder, in

   figures 459 to 462. Many new species were brought to this country by

   Mr. Cuming, and are represented in parts 24, 25, 28, 29; 32, 33, 36,

   37; 54, 55, 56, 57; 147, 148; 151 to 158 of the Conchological

   Illustrations, by G. B. Sowerby, jun.