Part 21

CAPRELLA. ----? PLEKOCHEILUS, Guild. AURICULA Caprella, Lam.

CAPRINA. D'Orb. DICERAS. Auct.?

CAPRINUS. Montf. (Conch. Syst. t. 2. p. 143.) The figure appears to be intended to represent Helix Nux-denticulata.

CAPSA. Brug. Fam. Nymphacea, Lam.--Descr. Equivalve transverse, subequilateral, subtrigonal; cardinal teeth, two in one valve, one notched in the other; lateral teeth remote, obsolete; an external ligament; two muscular impressions in each valve; a large sinus in the muscular impression of the mantle.--Obs. This genus is so nearly related to Donax, that it is difficult to distinguish it at first sight. The Capsæ, however, have not the short, plain, straight, posterior side, the distinct lateral teeth, nor the crenulated margins which characterize nearly all the Donaces. They are found in the British Channel, Brazil, and coast of Pacific Ocean. They are known from Erycina by not having the pit in the hinge for the ligament. Fig. 109. C. Braziliensis.

CAPULUS. Montf. Fam. Calyptracea, Lam.--Descr. Obliquely conical, posteriorly recurved; apex pointed, sub-spiral; aperture large, rounded, oval; with two muscular impressions, lateral, meeting behind; epidermis horny, rather velvetty. Britain, Mediterranean, West Indies, California, Australia.

CARDIACEA. (Cardiacées, Lam.) A family of the order Conchifera Dimyaria, Lam. Most of the genera of shells contained in this family are included in the very extensive family of Conchacea, in the system of De Blainville. They are described as having irregularly formed cardinal teeth, generally accompanied by one or two elongated lateral teeth. Most of the species are ventricose, and have regular radiating ribs. This family contains the genera Cardium, Cardita, Cypricardia, Hiatella, Isocardia, and others enumerated in the explanation of figures 122 to 130. Their characters may be thus explained.

1. CARDIUM. Two cardinal and two lateral teeth in each valve, including Hemicardium, Papyridea and Aphrodita, in the last of which the teeth are nearly obsolete. Fig. 122, 123, 123*, 123**.

2. VENERICARDIA. Two oblique cardinal teeth, one elongated; including Cardita, which has the umbones nearly terminal. Pachymya may probably be included, but the hinge is not known. Fig. 121, 124, and 130.

3. HIPPOPODIUM. One elongated cardinal tooth. Fig. 129.

4. MEGALODON. Hinge broad, septiform, with a large tooth in the centre of one valve. Fig. 127.

5. ISOCARDIA. Teeth laminar; umbones spiral. Fig. 126.

6. CARDILIA. The same, with a septiform posterior laminar tooth.

7. HIPPAGUS. Shaped like Isocardia, without teeth. Fig. 128.

CARDILIA. Desh. Fam. Cardiacea, Lam. A genus formed for the reception of Isocardia semi-sulcata, Lam. and a small fossil shell, which Deshayes had formerly named Hemi-cyclonosta Michelini; thus described, (translation) "shell oval, oblong, longitudinal, white, heart-shaped, ventricose, with large prominent umbones; hinge with a small cardinal tooth and a pit at the side; a spoon-shaped projection for the reception of the internal ligament; anterior muscular impression rounded, not deep; the posterior being upon a thin, horizontal lamina, projecting in the anterior." Deshayes further remarks that although the animal is unknown, the relations of the genus may be established by means of the shell alone. Two families contain all the shells which have the internal ligament inserted in a spoon-shaped projection; in the one, that of the Anatinæ, the ligament is supported upon a little bone, which is not soldered to the hinge; in the other, that of the Mactraceæ, this little bone has no existence. In the former, all the shells are inequivalve; in the latter equivalve. And M. Deshayes, considering that the valves are equal, and that there is no separate bone to the hinge, is of opinion that the genus ought to be placed near the Lutrariæ, and not far from the Anatinæ. C. semisulcata, fig. 501, 2.

CARDINAL MARGIN. The edge of a bivalve shell on which the teeth is placed.

CARDINAL TEETH. The teeth upon the hinge directly beneath the umbones of a bivalve shell, as distinguished from the lateral teeth, which are placed at a distance on each side. In Venus, fig. 119, the cardinal teeth, are marked by the letter c.

CARDIOCARDITES. Bl. A genus separated from CARDITA, Auct. Thus described (translation) "oval species, with the inferior margin nearly straight, or a very little inflated, crenulated and completely closed. Ex. La C. Ajar, Adans Seneg. pl. 16. fig. 2."

CARDISSA. Sw. A genus composed of those species of CARDIUM Auct. which are heart-shaped. Ex. C. dionæum, fig. 122. And C. Cardissa.

CARDITA. Brug. Fam. Cardiacea, Lam. Submytilacea, Bl.--Descr. Equivalve, inequilateral, ovate, subquadrate or oblong, marked externally by ribs radiating from the umbones and terminating in a crenulated margin on the inner surface; cardinal teeth in one valve, one long, thick, oblique; another short, more straight; in the other valve one long, oblique, thick. Muscular impressions two in each valve, rather oval; palleal impression not sinuated.--Obs. This description includes Lamarck's genus Venericardia, which, although consisting of the more oblong species, is not considered sufficiently distinct to justify the separation. Cypricardia is distinguished from this genus by a remote lateral tooth. Mediterranean, Africa, East Indies, &c. Cardita calyculata, fig. 124.

CARDIUM. Auct. Fam. Cardiacea, Lam. Conchacea, Bl.--Descr. Equivalve, sub-equilateral, sometimes gaping posteriorly, ornamented on the outside by ribs radiating from the umbones; cardinal teeth, two in each valve, locked into each other crosswise, lateral teeth, two in each valve, remote; muscular impressions, two in each valve; palleal impression entire. Ligament external, inflated.--Obs. Although this genus includes many remarkable forms, the characters are so easily defined that there is no difficulty in distinguishing it from any other genus. C. angulatum, fig. 123. C. Groenlandicum, fig. 123*. APHRODITA, Lea. C. Hemicardium, fig. 123**. fig. 122. C. Dionæum. It is somewhat surprising that this genus, which contains some of the most beautiful forms of bivalve Testacea, should have been left till quite lately without any attempt to revise the species and settle the synonyms. The author of this Manual has endeavoured to remedy this defect by publishing a catalogue of all the species hitherto known, which amount to 97, including many new species described by him in the "Proceedings of the Zoological Society," in 1840. Parts 46 to 51, 149 and 150, and 177 to 184 of his Conchological Illustrations contain figures of 60 species. Cardia are frequent in all climates.

CARINARIA. Auct. Class, Cephalopoda. Division, Monothalamia, Lam. Fam. Nectopoda, Bl.--Descr. Symmetrical or nearly so, conical, thin, glassy, fragile, patelliform; with a fimbriated dorsal keel; apex convolute, bent forwards; aperture oval, pointed at the dorsal extremity. Hab. Amboyna, Indian Ocean, and Mediterranean Sea.--Obs. A most singular and beautiful shell, remarkable for its transparency, its fragile structure, and the dorsal keel, whence it derives its name. It was once so rare that a single specimen was known to realize one hundred guineas. Fig. 488. C. Mediterranea.

CARINATED. (From Carina, a keel.) Applied to any shell having a raised, thin ledge, passing round a whorl or any other part of a shell, as in Carinaria, fig. 488.

CARINEA. Sw. A genus formed for the reception of OVULUM gibbosum, Auct. and similar species, fig. 443.

CARINELLA. Adanson. LUTRARIA papyracea, Lam. LIGULA, Leach. Fam. Mactracea, Lam. Fig. 77.

CARINIDEA. Sw. A sub-genus of the genus Canthorbis, Sw. (Turbo.) thus described, "Imperforate; spire pyramidal, acute; basal whorl concave beneath, and carinated round its circumference; aperture oval, entire, slightly angulated at the base of the pillar, which turns inwards. C. concavus, Martini, 168, fig. 1620, brevispinosus? Sow. Gen. (Turbo,) fig. 1."

CAROCOLLA. Auct. Fam. Colimacea, Lam.--Descr. Orbicular, depressed, with the outer sides of the whorls angulated or keeled, whorls few; peritreme reflected; columella contiguous to the axis; epidermis thin.--Obs. This genus differing from Helix only in the whorls being angulated, is hardly distinct enough from the latter to justify the separation. In De Ferrusac's system these species constitute the division Helicigona, of the genus Helix. C. Lamarckii, fig. 277. East and West Indies, Philippines, South America and Europe.

CARTILAGE. See LIGAMENT.

CARYCHIUM. Müll. Fam. Auriculacea, Bl. Colimacea, Lam.--Descr. Oblong or cylindrical, with gradually increasing whorls, few in number; aperture straight, short, with a fold on the columella.--Obs. This genus of minute land shells differs from Auricula chiefly in the soft parts. De Furrusac enumerates three species, C. Lineatum, C. Corticaria, (Odostomia, Flem.) and C. Minimum, fig. 301. De Blainville places it in his genus Auricula, as "species with two folds and a posterior tooth on the columella," giving a figure of A. Mysotis as his example, and quoting the name Phitia, Gray. Europe.