Conch shell

“ Oblong, turrited, rather ventricose, solid; aperture generally lengthened, terminating posteriorly in a short canal, and anteriorly in an emargination or truncated canal; outer lip, when young, thin; when full grown, thickened and expanded, lobed at the spiral extremity, sinuated anteriorly near the caudal canal.—Obs. This well known genus includes some species of immense size, commonly called conch shells. Most of the recent species are brought from the Indian Ocean. Very few fossil species are known. The young shells have very much the appearance of cones, the outer lips being thin. ”

“ In late Roman work at Baalbek and Palmyra and in Renaissance buildings shells are frequently carved in the heads of circular niches. A low class of the negro or other inhabitants of the Bahamas and the Florida Keys are sometimes called “Conches” or “Conks” from the shell-fish which form their staple food. ”

“ Near his mouth he has two feelers, such as insects have, to touch things.
[Pg 73]
Where the feelers join his head he has two eyes.
His foot is flat, and is as big as all the rest of his body. It is just the size of the open part of his shell. Why is that?
The shoe on his foot is hard, like horn. When he draws back into his shell, that shoe is his door. It fits close. It shuts him in safe in his shell.
LESSON XXXV. THE STORY OF MR. CONCH.
The conch or winkle does not like to live in sand, or on hard rock. He likes deep water, where he has some sand and some rock. ”

“ The graceful curves and the delicate tints of lovely pink color make it exceedingly attractive. The conch abounds in the waters of the West Indies, especially in the Bahamas, where many 78thousands are annually taken for the shell, which forms quite an article of commerce. The flesh is esteemed as food and is also used for bait; and it is particularly in preparing for these purposes that the pearls are found, as no established fisheries exist for the pearls alone. ”

“ The mouth remains in many species constantly open, even when the frontal fissure is closed (figs. 7, 16) . Since the centre of the shell mouth lies in the prolongation of the proboscis arising from the operculum of the central capsule, probably the main stream of sarcode, issuing from the latter, becomes protruded by the former.
Apophyses of the shell (besides the teeth of the margins) are completely wanting in three genera, Concharium, Conchellium, and Conchopsis (Pl. 123, figs. 1-4, 7; Pl. 125) . The four other genera possess free apophyses or spines, which we call horns. ”

“ This division comprehends not only the Mollusca, but also the Testacea of Aristotle and of Pliny, and, of course, had reference to molluscous animals in general—of which the greater portion have shells.
A treatise concerning the shells, exclusively, of this greater portion, is termed, in accordance with general usage, a Treatise upon Conchology or Conchyliology; although the word is somewhat improperly applied, as the Greek conchylion, from which it is derived, embraces in its signification both the animal and shell. Ostracology would have been more definite. ”

“ Tasting a small piece will immediately tell, if the species is not known, whether it is edible or of the styptic kind.
* Stem excentric. P. concha ́tus Fr.—Formed like concha, a shell-fish. Pileus about 2333 in. across, tough and flexible, unequal, excentric or dimidiate, margin often lobed, cinnamon-color becoming pale, at length more or less scaly. Flesh thin. Gills narrow, forming decurrent lines on the stem, somewhat branched; pinkish-white then pale-ochraceous. Stem about 2⁄3 in. long, 3–4 lines thick, solid, unequal, pale, base downy. Massee. ”

“ The Concholepas is much the most abundant, and the best preserved shell; but I extracted perfectly preserved specimens of the Fissurella biradiata, a Trochus and Balanus (both well-known, but according to Mr. Sowerby yet unnamed) and parts of the Mytilus Chiloensis. Most of these shells, as well as an encrusting Nullipora, partially retain their colour; but they are brittle, and often stained red from the underlying brecciated mass of primary rocks; some are packed together, either in black or reddish moulds; some lie loose on the bare rocky surfaces. ”

“ Definition.—Concharida with dentate lateral margins and a sharp sagittal keel of the compressed valves, without horns on the hinge.
The genus Conchopsis and the following Conchoceras differ from the other Concharida in the strong lateral compression of the shell, so that each valve is provided in the sagittal plane with a sharp prominent keel, comparable to the dorsal and the anal fin of fishes. These compressed shells are in general twice to three times as large as the more roundish and keelless shells of the five preceding genera. ”

“ But it is not alone the beauty of shells that renders them interesting. Conchology, which treats of shells, is as a science at least as old as the days of Aristotle, the study of which was resumed, along with that of the other sciences, when the dark ages had passed away. Since the beginning of the nineteenth century it has given place to a more extended and comprehensive study of molluscous animals, the presence or absence of a shell having been found not to constitute one of the most important characteristics which distinguish different classes of mollusks. ”

“ Conchs of a large size were abundant, and there were myriads of little rice-shells.
"I wonder if these shells can be put to no use?" asked Harold.
"Certainly," Robert responded. "If we need lime we can obtain it by burning them. These large round shells may be cut so as to make handsome cups and vases. The long ones are used by many poor people for spoons. And the conch makes a capital trumpet; our negroes on the seaboard make a hole in the small end for this purpose. We often hear the boatmen blowing their conchs at night ”

“ They are all covered with an epidermis, beneath which is generally a smooth surface, with sometimes a high polish; a few are granulated and tuberculated. They are found in great abundance in the seas of warm climates.
Shell conic, covered with a membranous periosteum, thick, solid, involuted; the summit of the cone anterior; the spire little or not at all projecting; aperture longitudinal, very narrow, turning towards its anterior extremity; the external edge straight, with oblique plaits in its anterior part; operculum very small and horny, sub-spiral, with summit terminal. ”

“ 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. ”

“ This family, of which between 400 and 500 22distinct kinds are known, is a great favourite with collectors on account of the brilliant colours and various patterns of the shells. Some, owing to their beauty and rarity, have been sold at very high prices, as much as £50 having been paid for a single shell. The Cones are found in all tropical seas, but are rare in cold or temperate latitudes. None are met with on our own shores, one species alone being known from the Mediterranean. They occur fossil in the Chalk and Tertiary strata. ”

“ Shell smooth, fulvous-white, with broad dark chesnut bands and transverse lines of dots; spire obtuse, convex, striated, depressed.
C. augur. Lamarck Annal. Mus. xv. 277. Encycl. Méth. 333. 6.
Conus magus. Gmelin 3392. 57. Martini ii. 58. 641.
The Girdled Cone is conspicuous among the beautiful shells of this extensive family, by the broad and rich chesnut bands, which are either two or three in number, and more or less broken into spots; in high-coloured shells the minute lines of dots between them are also of the same colour. It is not a common species, and inhabits the Asiatic ocean. ”

“ It is, in a more complicated degree, a variant of Bernouilli’s ‘Eadem mutata resurgo:’ the logarithmic conic curve becomes a logarithmic plane curve.
A similar geometry is found in the other shells with elongated cones, Turritellae, Spindle-shells, Cerithia, as well as in the shells with flattened cones, Trochidae, Turbines. The spherical shells, those whirled into a volute, are no exception to this rule. All, down to the common Snail-shell, are constructed according to logarithmic laws. The famous spiral of the geometers is the general plan followed by the Mollusc rolling its stone sheath. ”

“ In some shells the operculum is small, in others large, and progressing step by step we find some, such as the scallop and oyster, [Pg 9] with one side round, and the other (really an operculum) flat and as large as the shell; until we come to the perfect type with each valve the same shape and size. Then the operculum disappears, as in the limpet, and the covering shell becomes smaller and smaller, till in the Scutum ambiguum (Plate IX., Fig. 23) the shell bears about the same proportion to the animal that the little bonnet, fashionable a few years ago, bore to the lady that wore it. ”

“ Several are found on British coasts, but they are not remarkable for beauty.
"The top-shell, Trochus, is univalve, conic, spiral; the aperture either angular or rounded; columella oblique: some of the apertures have a tooth-like projection. (Plate 7.) Species, one hundred and thirty. Several kinds occur in « 34 » Britain. New Zealand, Friendly Isles, Red Sea, and most other seas, afford the various species. Two of this genus have the power of collecting parts of shells and other testaceous substances, which adhere strongly to the whorls of the shell: it is called the Conchologist. ”

“ The shell is heavy; the body whorl contracted at the upper part, where the margin is sharply carinated; the spire much depressed and concave; each volution is also concave, and has from three to four fine grooves, which occupy its full extent, and which appear minutely granulated ”

“ So easily collected, arranged, and preserved, and withal so singular and graceful in form, and rich and various of tint, one cannot wonder that Shells have always had a conspicuous place in all museums, and other collections of natural history objects; neither can we feel surprised that a high value should have been set upon rare specimens; as much as a thousand pounds it is said has been given for the first discovered specimen of the Venus Dione; another shell called the Conus cedo nulli, is valued at three hundred pounds ”

“ In this way, too, some members of the genus solen force their way through the sand; while those called Tellina spring to a considerable distance, by first folding the foot into a small compass, and then suddenly expanding it, closing the shell at the same time with a loud snap; so that you see these sober-looking mollusks are sometimes frolicksome fellows; this is an enforcement of the lesson, judge not by appearances.
Some of the species, both of the Mussel and Cockle families, [54] have very beautiful shells. ”

“ Pteropoda, containing Atlanta, Spiratella and Argonauta.
NUCLEUS. (A kernel.) Anything forming a centre around which matter is gathered. The nucleus of shells is the first formed part; the first deposit of shelly matter to which the successive layers are added; the apex of the spiral cone, of which most shells are composed. (See Cone.) The nucleus is formed within the egg in oviparous, and within the old shell in viviparous mollusca. It is frequently more transparent and light than the remainder of the shell, and sometimes falls off; when this occurs the shell is said to be decollated. ”

“ Swainson tells us that the animals of these shells affix themselves to other bodies by a [57] particular muscle, which is protruded through the gaping part of the valves; they also adhere, when young, by means of the bissiform epidermis, or bissus-like outer skin: this species is a native of the Atlantic Ocean and the seas of Europe. The Antique Ark, (A. antiqua,) is very like the Common Cockle, being of a white colour, and heart-shaped. We give below a representation of this shell, and also of the shell of the pretty little Pearly Trigonia, (T. margaritacea,) included in the Arcadæ family ”

“ The first is Conus, a large and beautiful genus, including many rare and valuable species. Shell univalve, turbinate, aperture effuse, or having the lips separated by a sinus, linear, without teeth, pillar smooth. In their natural state the shells are usually covered with an epidermis; but will bear a brilliant polish. C. textilis, cloth of gold, is valuable. C. generalis is sometimes sold for twenty guineas. The example on the table is C. Ebræus, or Hebrew cone. (Plate 6.) Species one hundred and fifty-five; not one British. The greater number are brought from the Indian Ocean ”

“ Dimensions.—Length of the shell 0.2, height 0.15, breadth 0.1.
Habitat.—Central Pacific, Stations 271 and 272, surface, and at various depths.
6. Conchidium argiope, n. sp. (Pl. 124, figs. 7-9) .
Shell laterally compressed, with three different dimensive axes of the proportion = 6 : 5 : 3. Both valves nearly equal. Margins of the shell dentate along the lateral fissure, on each side of one valve thirteen or fourteen thin conical teeth. Aboral hinge with two equal, short, pyramidal horns. Mouth with two equal short lips. Pores subregular, circular, twice as broad as the bars. ”