Part 5

Cytherea lusoria. C. petechialis. C. impudica. C. castanea. C. zonaria. C. graphica. C. morphina. C. purpurata. C. casta. C. corbicula. C. meretrix. C. gigantea. C. erycina. C. lilacina. C. impar. C. erycinella. C. pectoralis. C. planatella. C. florida. C. nitidula. C. Chione. C. maculata. C. citrina. C. albina. C. lata. C. mactroides. C. trigonella. C. sulcatina. C. Hebræa. C. castrensis. C. ornata. C. picta. C. tigrina. C. scripta. C. numulina. C. muscaria. C. pectinata. C. gibbia. C. ranella. C. testudinalis. C. divaricata. C. cuneata. C. placunella. C. rugifera. C. tripla. C. Venetiana. C. juvenilis. C. rufa. C. Guiniensis. C. Dione. C. Arabica. C. trimaculata. C. immaculata. C. pellucida. C. hepatica. C. lucinalis. C. lactea. C. exoleta. C. lincta. C. concentrica. C. prostrata. C. interrupta. C. tigerina. C. punctata. C. umbonella. C. undatina. C. pulicaris. C. mixta. C. abbreviata. C. plicatina. C. flexuosa. C. macrodon. C. lunularis. C. squamosa. C. lunaris. C. cardilla. C. cygnus. C. dentaria.

_C. Chione._ The Chione Cytherea.

Thick, solid, heart-shaped, covered with a smooth brown epidermis, beneath which the shell is of a beautiful purple; radiated longitudinally, faintly wrinkled transversely, anterior cardinal tooth entire, and without a striated canal; apex turned sideways, with a cordiform depression.

_C. mactroides._ The Mactra-like Cytherea. Pl. 9, fig. 4.

Species thin, convex, triangular; summits very marked; margins sharp; anterior cardinal tooth entire.

_C. pectinata._ The pectinated Cytherea.

Species oval, thick, solid, more or less compressed, costated, pectinated upon the edges.

6. Venus. Eighty-eight species.

This genus of shells is numerous and varied. It surpasses all bivalve shells in beauty, and is in form very like the Cytherea, but easily distinguished by the hinge, which almost invariably contains three approximate teeth, and a lateral tooth diverging to the summit. The internal margin of the valves is crenated or dentated, with or without lamellar striæ.

The shells are of the most beautiful and lively tints; the exterior as well as the interior colouring is of almost every possible shade and hue. They are found buried a little below the surface on the sandy shores of most parts of the world, particularly in warm climates.

Shell solid, thick, regular, perfectly equivalve and close, more or less inequilateral; summits well marked, inclined anteriorly; hinge sub-similar; the middle cardinal tooth forked, or three cardinal teeth more or less contiguous and convergent towards the summit; ligament thick, often arched, convex, and exterior; two distant muscular impressions; cordiform depressions beneath the beaks.

Venus puerpera. V. reticulata. V. pygmæa. V. corbis. V. verrucosa. V. rugosa. V. casina. V. crebiscula. V. crenulata. V. discina. V. granulata. V. marica. V. cingulata. V. cardivides. V. grisea. V. elliptica. V. Dombeii. V. mercenaria. V. lagopus. V. gallina. V. gallinula. V. pectinula. V. sulcata. V. lamellata. V. exalbida. V. rufa. V. dorsata. V. hiantina. V. crassisulca. V. corrugata. V. Malabarica. V. papilionacea. V. adspersa. V. punctifera. V. turgida. V. literata. V. florida. V. petalina. V. bicolor. V. floridella. V. catenifera. V. pulchella. V. sinuosa. V. tristis. V. plicata. V. cancellata. V. pectorina. V. sulcaria. V. textilis. V. texturata. V. geographica. V. rariflamma. V. decussata. V. pullastra. V. glandina. V. truncata. V. retifera. V. anomala. V. galactites. V. exilis. V. scalarina. V. Scotica. V. aurea. V. virginea. V. marmorata. V. ovulæa. V. laterisulca. V. callipyga. V. opima. V. nebulosa. V. phaseolina. V. carneola. V. flammiculata. V. conularis. V. strigosa. V. aphrodina. V. Perronii. V. aphrodinoides. V. elegantina. V. flammea. V. rimularis. V. vulvina. V. vermiculosa. V. subrostrata. V. undulosa. V. pumila. V. ovata. V. inquinata.

_V. Casina._ The Casina, or broad-ribbed Venus. Pl. 8, fig. 2.

Sub-orbicular, with transversely acute recurved ridges; lamellar striæ; crenulated on the hind margin; slightly channelled behind the depression.

_V. decussata._ The intersected Venus. Pl. 9, fig. 3.

Species sub-rhomboidal, with decussated striæ; margin not denticulated; umbo placed near one end; the three teeth of the hinge very contiguous and very weak; exterior brownish and marked with purple lines.

_V. aurea._ The golden Venus.

Sub-orbicular, inequilateral, transversely and concentrically striated; yellow golden colour.

_V. corbis._ The basket Venus.

Species sub-rhomboidal, deeply latticed; teeth very thick, ligament entirely concealed, margin dentated.

_V. puerpera._ The convex or spotted Venus.

Species thick, solid, orbicular or sub-orbicular, with concentric striæ, or, rather, laminæ; teeth very thick; margin dentated.

_V. granulata._ The granulated Venus.

Species thick, solid, cardium-shaped, radiated from the summit to the base.

7. Venericardia. One species.

This genus resembles the Venus, but has only two oblique cardinal teeth on each valve.

Shell equivalve, inequilateral, sub-orbicular, sides generally with longitudinal rayed ribs; hinge with two oblique cardinal teeth in each valve, turned in the same direction.

_V. imbricata._ The imbricated Venericardia. Pl. 9, fig. 1.

Species almost round, having convex longitudinal ribs, covered with imbricated rough scales; inferior margin rounded and dentated; more and more equilateral; the two teeth short and oblique.

FAMILY X. CARDIACEA. Five genera.

1. Cardium. Cockle, or Heart Shell. Forty-eight species.

This genus received its name from its resemblance to a heart (καρδια). It is so well defined by Linnæus that no alteration was made by Lamarck, except in making two divisions of them; the first distinguished by having the anterior side as large or larger than the posterior, and no distinct angle at the apex; the second by possessing carinated or angular umbones, and the posterior side often much larger than the anterior. These shells are found at a small depth in the sand on almost every seashore.

Shell inflated, equivalve, sub-cordiform (when seen anteriorly), generally costated from the summit to the circumference; summits very evident; slightly recurved forward; hinge complex, similar, formed by two oblique cardinal teeth, articulating with the corresponding teeth on the other valve; two distant lateral teeth on each valve; ligament dorsal, posterior, and very short.

Cardium costatum. C. Indicum. C. ringens. C. Asiaticum. C. tennicostatum. C. fimbriatum. C. pseudolima. C. aculeatum. C. erinaceum. C. tuberculatum. C. Brasilianum. C. apertum. C. papyraceum. C. bullatum. C. ciliare. C. echinatum. C. lævigatum. C. biradiatum. C. eolicum. C. pectinatum. C. isocardia. C. muricatum. C. angulatum. C. marmoreum. C. elongatum. C. ventricosum. C. rugosum. C. sulcatum. C. serratum. C. unedo. C. medium. C. fragum. C. retusum. C. tumoriferum. C. rusticum. C. edule. C. Groenlandicum. C. latum. C. crenulatum. C. exiguum. C. minutum. C. roseum. C. scobinatum. C. hemicardium. C. cardissa. C. inversum. C. Junoniæ. C. lineatum.

_C. edule._ The edible Cardium, or common Cockle. Pl. 10, fig. 2.

Species not gaping, with about twenty-six depressed ribs and transverse obsolete scales; of a cream colour; beaks protuberant.

_C. cardissa._ Venus’s Heart.

Species heart-shaped, valves angularly flattened, umbones alternating.

_C. lævigatum._ The smooth Cardium.

Species smooth or nearly so, anterior side as large as the posterior.

_C. hemicardium._ The half-heart Cardium.

Species ribbed, with elevated rough striæ; the anterior side is very short and almost flat.

_C. costatum._ The high-ribbed Cardium.

No angle at the umbones; anterior side at least as large as the posterior; rows of white, hollow, elevated ribs, situated at regular distances, proceeding from the umbones to the margin, with the spaces between them of a reddish brown colour.

_C. unedo._ The Strawberry Heart.

Species with ribs armed with small crescent-shaped scales.

_C. tuberculatum._ The tuberculated Cardium.

Species not gaping, with large ribs armed with nodules.

2. Cardita. Twenty-one species.

Lamarck took this genus from the Chama on account of several peculiarities in the shell as well as in the animal. It is not affixed to other bodies by its lower valve, but, according to De Blainville, lies exposed on the rocks. There is some difficulty in distinguishing this genus from the Venericardia, without carefully examining the position of the two teeth.

Shell regular, thick, solid, equivalve, more or less inequilateral; summit dorsal, always very recurved anteriorly; hinge similar, formed by two oblique teeth; one short cardinal placed beneath the umbo, the other oblique, arched, marginal, and prolonged; ligament elongated, sub-exterior, and inserted; two very distinct muscular impressions.

Cardita sulcata. C. ajar. C. turgida. C. squamosa. C. phrenetica. C. crassicosta. C. rufescens. C. calyculata. C. subaspera. C. nodulosa. C. intermedia. C. trepezia. C. bicolor. C. depressa. C. concamerata. C. sinuata. C. aviculina. C. citrina. C. sublævigata. C. corbularis. C. lithophagella.

_C. crassicosta._ The thick-ribbed Cardita.

Species elongated, a little gaping at the inferior margin; ligament concealed.

_C. sulcata._ The furrowed Cardita. Pl. 10, fig. 3.

Sub-cordiform or oval, more transverse than longitudinal; colour white, tesselated with brown; posterior depression heart-shaped; longitudinal, convex, transversely-striated ribs.

3. Cypricardia. Four species.

Distinguished from the Cardita by having three teeth beneath the apices, and a callous lengthened tooth or ridge.

Shell obliquely elongated, equivalve, inequilateral; valves striated, but never ribbed; hinge with three teeth beneath the umbo, and one lateral elongated tooth.

Cypricardia Guinaica. C. angulata. C. rostrata. C. coralliophaga.

_C. Guinaica._ The Guinea Cypricardia. Pl. 10, fig. 6.

Species elongated, very inequilateral; summit rounded and recurved anteriorly; two short divergent cardinal teeth, besides a lamellous tooth; ligament very long, projecting or not; yellowish white, covered with decussated striæ.

4. Hiatella. Two species.

Established by Daudin; classed by Linnæus with the Solen, but Lamarck is of opinion that it more nearly approximates the Cardita.

Shell thin, sub-rhomboidal, equivalve, very inequilateral, gaping at its inferior margin and posterior extremity; the summit very anterior and recurved in front; dorsal hinge formed by a single tooth on one valve corresponding to a semicircular slope on the opposite valve, or by a small tooth with a cardinal cavity in each valve; ligament probably exterior and dorsal; muscular impressions unknown.

Hiatella Arctica. Hiatella biaperta.

_H. Arctica._ The Arctic Hiatella.

Shell small, transversely oblong; apices truncated, with two divergent spring ridges; a small tooth on each valve; cream colour, with decussated striæ; inside pearly.

_H. biaperta._ The double-clefted Hiatella. Pl. 10, fig. 4.

Species that has only a single tooth on one valve; yellowish white.

5. Isocardia. Three species.

Taken from the Chama of Linnæus on account of a peculiarity in the shape of the cardinal teeth, and the singular curvature of the umbones.

Isocardia cor. I. semisulcata. I. Moltkiana.

_I. cor._ The heart Isocardia. Pl. 12, fig. 4.

Shell free, regular, heart-shaped, equivalve, very inequilateral; summits diverging, strongly recurved spirally, forward, and outward; hinge dorsal, long, similar, formed by two flat cardinal teeth, with an elongated lateral one behind the ligament, which is dorsal and exterior, diverging towards the summits; muscular impressions very distinct and rather small; slightly wrinkled longitudinally; exterior reddish chestnut colour, interior white.

The Isocardia Moltkiana is a very rare shell, and the most elegant species of this genus.

FAMILY XI. ARCACEA. Four genera.

1. Cucullæa. One species.

Distinguished from the Arca by the muscular impression within, to one side of which is an ear-shaped testaceous appendage; the shell is more trapeziform, and the hinge by age becomes obsolete, giving the teeth a more horizontal appearance.

Shell equivalve, inequilateral, trapeziform, heart-shaped; beaks distant, and separated by the angular groove of the ligament, which is altogether external; hinge linear, straight, with small transverse teeth, having at its extremity from two to five parallel ribs; valves marked with minute and strong longitudinal striæ, and sometimes one valve overlaps; margins crenulated.

_C. auriculifera._ The eared Cucullæa. Pl. 10, fig. 1.

Species navicular or obliquely heart-shaped, with decussated striæ; hinge completely straight, with two parallel ribs at each end, the terminal teeth longer and more oblique than the others; exterior chestnut colour, interior white, tinged with violet.

2. Arca. The Ark. Thirty-seven species.

This genus is easily known by its resemblance to the hull of a ship; the hinge is peculiar, being composed of numerous sharp teeth alternately inserted between each other. The Arca of Linnæus was divided by Lamarck into the four genera that compose this family, each possessing a strong distinctive character. All the shells of this family are found in the sea at a little distance from the shore; they are covered with a dark greenish lamellar or velvet-like epidermis, frequently ending in a deep fringe at the margin.

Shell a little varied in form, but most generally elongated, and more or less oblique at the posterior extremity; sometimes very inequilateral; summits more or less distant, and a little recurved forward; hinge anomalous, straight, or a little curved; long, and formed by a line of short vertical teeth decreasing from the extremities to the centre; ligament exterior, broad; sometimes the margin is crenated.

Arca tortuosa. A. semitorta. A. Noæ. A. tetragona. A. umbonata. A. sinuata. A. avellana. A. cardissa. A. ventricosa. A. retusa. A. sulcata. A. ovata. A. Helbingii. A. scapha. A. barbata. A. fusca. A. Magellanica. A. Domingensis. A. lactea. A. trapezina. A. pistachia. A. pisolina. A. cancellaria. A. callifera. A. irudina. A. bisulcata. A. Indica. A. senilis. A. antiquata. A. rhombea. A. granosa. A. auriculata. A. Brasiliana. A. corbicula. A. squamosa. A. Cayennensis. A. inequivalvis.

_A. Noæ._ Noah’s Ark. Pl. 10, fig. 5.

Species boat-shaped, oblong, striated transversely and ribbed longitudinally; umbones remote and incurvated; margins entire and gaping; hinge straight; whitish, with divergent zigzag chestnut stripes; inside bluish white.

_A. tortuosa._ The twisted Ark.

A rare species; shell elongated, close, twisted; hinge completely straight.

_A. barbata._ The bearded Ark.

Species with the hinge straight, not hollowed or not gaping inferiorly, and of which the muscle is not adherent.

3. Pectunculus. Nineteen species.

This genus has the ligament partially inserted internally, and has no exterior angular groove. The valves never gape, often have rayed longitudinal ribs, are compressed, and the shell by age becomes thick and ponderous, sometimes attaining a large size. The teeth in the hinge are not so numerous as in the Arca and Cucullæa; the centre teeth appear worn down.

Shell close, orbicular, doubly convex, equivalve, sub-equilateral; summits almost vertical, and more or less distant; hinge formed on each valve by a rather numerous series of small teeth, disposed in a curved line, sometimes broken under the summit; ligament external and large.

Pectunculus glycimeris. P. pilosus. P. undulatus. P. marmoratus. P. scriptus. P. angulatus P. stellatus. P. pallens. P. violacescens. P. zonalis. P. pennaceus. P. rubens. P. castaneus. P. pectiniformis. P. striatularis. P. nummarius. P. pectinatus. P. radians. P. vitreus.

_P. glycimeris._ The delicious Pectunculus.

Sub-orbicular, umbones produced; finely striated transversely and longitudinally; covered with epidermis, under which it is marked with reddish chestnut spots or bands; inside white; margins crenulated.

_P. pilosus._ The hairy Pectunculus.