Part 4
But about the Imperial Trochus, with its “orbicularly conical” shell—that term we may explain as round and cone-like; a reference to Fig. 4, Plate IV, will shew what is meant by this more clearly than words can, and likewise exhibit the beautiful markings of this species, with its ground tint of rich violet brown. This beauty is often obscured by calcarious incrustations, and marine plants, shewing that the mollusk is sluggish in its habits—a slothful creature. So it is with human beings, sloth covers and hides the good qualities and virtues with an overgrowth at all times difficult to remove, and oftentimes destructive of all that is fair and good in the character.—Children, be not slothful! The Obelisk Trochus, (_T. obeliscus_,) is a rare white and green shell, sometimes seen in collections; it is of a conico-pyramidal form, not remarkable for beauty, and is a native of the Indian seas.
Mr. Gosse speaks of the Tops and Winkles as among the most useful inhabitants of the Aquarium; they mow down with their rasping tongues the thick growth of _Confervæ_ which would otherwise spread like a green curtain over the glass walls of the tank, and obstruct the view of its inhabitants. Here is this author’s description of the beautiful piece of mechanism by which this work is effected:—“The appearance and position of the organ would surprise any one who searched for it for the first time, and as it is easily found, and as Periwinkles are no rarities, let me commend it to your examination. The easiest mode of extracting it, supposing you are looking for _it_ alone, is to slit the thick muzzle between the two tentacles, when the point of a needle will catch and draw out what looks like a slender white thread, two inches or more in length, one end of which is attached to the throat, and the other, which is free, you will see coiled in a beautiful spiral manner, within the cavity of the stomach.
By allowing this tiny thread to stretch itself on a plate of glass, which is easily done by putting a drop of water on it first, which may then be drained off and dried, you will find that it is in reality an excessively delicate ribbon, of transparent cartilaginous substance or membrane, on which are set spinous teeth of glassy texture and brilliancy. They are perfectly regular, and arranged in three rows, of which the middle ones are three-pointed, while on each of the outer rows a three-pointed tooth alternates with a larger curved one, somewhat boat-like in form. All the teeth project from the surface of the tongue on hooked curves, and all point in the same direction.”
And with this curious piece of mechanism the little Winkle works away and cuts down swathe after swathe of the minute vegetation, just as a mower does the meadow grass; only the mollusk eats as he goes, and so gets payment for his labour; the man has it in another and to him more useful form. We might tell a very long story about these Tops and Winkles, which are nearly related to each other, but must now pass on to describe the rest of the shells on Plate IV, which are the Perspective Solarium, (_S. perspectivum_,) Fig. 5, the generic name comes from _sol_—the sun, and viewed perspectively, that is, in such a position that the whole top of the shell is at once presented to the view, looking like a flat surface, it presents a circular appearance, marked with rings and rays like representations of the sun sometimes do.
The Variegated Solarium, (_S. variegatum_,) Fig. 6, is a small but very pretty shell, somewhat rare. The mollusk is remarkable on account of the singular shape of its operculum, which differs from that of all other species; it is of a cone-shape, and covered from top to bottom with what are called membranous lamellæ, that appear to stand out like little shelves winding up spirally. This singular form of operculum has been long known to naturalists, but it is not until lately that they have discovered to what species of testacean it belonged. Let us here explain that _operculus_ is the Latin for a cover or lid.
CONES, VOLUTES, MITRES, AND OLIVES.
These are names given by collectors to certain classes of univalve shells distinguished by peculiarities of formation, more or less distinct. We shall describe two or three of each, that our readers may have some idea of the meaning of the terms which are often used by those who speak or write on conchology.
The family of Cones, called _Conidæ_, is an extensive one, considerably above two hundred species having been discovered. Many of them are very beautiful both in shape and colour, so that they are highly valued by collectors; they are principally found in the southern and tropical seas, upon sandy bottoms, at depths varying from a few feet to seventeen fathoms. The shells are generally thick and solid, rolled up, as it were, into a conical form; the most familiar illustration that can be given of this form is a sugar-loaf, which all these shells more or less resemble in general outline, as thus—
[Illustration]
Cones are either plain or coronated, that is, crowned, having rows of projections round the top of the shell, like the second of the above figures; and this forms a mark of division into two classes, although these classes often run, as it were, one into the other; some plain cones having slight irregularities of surface, and some crowned ones being very nearly plain.
The Common, or Ordinary Cone, (_Conus generalis_,) Plate V. Fig. 1, is an elegantly-shaped and beautifully-marked shell, having much the appearance of being carved out of some rare kind of marble. The Lettered Cone, (_Conus littoralis_,) Fig. 2, appears to be scribbled over with Hebrew, Greek, or Arabic characters, and almost every species has something peculiar in its markings; clouds and veins, and dots, and stripes, and bands, of every conceivable shape and mode of arrangement, may be met with in these shells, whose surface, when the epidermis, or outer skin is removed, bears a beautiful polish. Curious names have been given to some of them, such, for instance, as the High Admiral, Vice Admiral, and Guinea Admiral, which indicate the rank they hold in the estimation of collectors. From five to twenty guineas is the price at which good and rare ones have been valued, and one, the _Conus cedo nulli_, which may be translated, the Cone second to none, has fetched the enormous sum of three hundred guineas. It must not be supposed that these shells exhibit all their beauties when, inhabited by a carnivorous, or flesh-eating mollusk, they move slowly about, or lie for a time motionless among the rocks and sand-beds of the ocean. The before-mentioned epidermis, which is the Latin for the outer skin of the human body, covers them like a cloak or mantle, which is the name it bears among naturalists. Much careful labour is required to bring them to a fit state for cabinet shells.
VOLUTES form an extensive family of shells under the name _Volutinæ_. The greater part are natives of tropical seas, and dwell far down so that they are seldom found on the coast, except after storms. There are a few European species, but these are not remarkable for beauty, as most of the others are. The generic name signifies twisted, or rather wreathed, as flowers or leaves might be, about some central object. In these shells the spire is generally short, as it is in many cones, sometimes scarcely apparent; the form is usually elegant, and the markings often striking and handsome. On Plate V, will be found three examples—Fig. 3 is the Undulated Volute, (_V. undulata_,) the Latin for a little wave is _undula_, and these marks are like the lines caused by the flowing of the waves on a sandy shore: this shell is found chiefly in the South Pacific; the animal which inhabits it is prettily-marked with zebra-like stripes. Fig. 4 is called the Pacific Volute, (_V. Pacificus_;) the shape, it will be seen, is somewhat different, being more angular, and it is without the waved lines. Fig. 5, the Bat Volute, (_V. vespertilio_,) is more decidedly knobbed or spiked, approaching nearly to the shape of some of the coronated ones. This species is found in the Indian seas; the specific name is the Latin for a bat.
MITRES; these are usually considered as a genus, or branch of the Volute family; the scientific name is _mitra_, the form is generally long, slender, and pointed—something like the bishop’s mitre, hence the common name of the genus. In the Episcopal Mitre, (_M. episcopalis_,) Plate VI, Fig. 1, we see this form in its greatest perfection; this is a handsome shell found in the Indian seas, and on the coasts of the South Sea Islands. The mollusk is remarkable for a long proboscis, double the length of the shell, the extremity of which swells into a club form, and has an oval orifice or opening: the specific name _episcopalis_, comes from the Latin, and means of, or like a bishop. The Tanned Mitre, (_M. adusta_,) from the Latin _adustus_—burned or parched, is, what is called fusiform and turretted, that is, shaped like a spindle, and having a spire or turret-like termination. The streaks of colour are transverse, that is, running the length of the shell, or in other words, they are longitudinal; this, too, comes from the South Sea Islands. Fig. 2 is the Wrinkled Mitre, (_M. corrugata_,) from the Latin _corrugo_—to wrinkle; it is very different both in shape and markings, from the last species; the whorls, it will be seen, are angulated or pointed above, and the lower part of the shell is much larger than the spiral or upper portion. It is a true mitre nevertheless, although not just such a one as a bishop would like to wear. It inhabits the Indian Ocean, the coast of New Guinea, etc.
OLIVES; these, for richness of colour and brilliancy of effect, will bear comparison with any genus of shells. Naturalists speak of them collectively as _Olivinæ_; they belong to the Volute family, and are said to number about eighty species. Most of those which have reached this country, have come from the Mauritius, where they catch them with lines baited with portions of Cuttle-fish. We have here depicted two of them, namely, the Figured Olive, Fig. 3, (_Oliva textilina_,) from the Latin _textilus_, which is woven or plaited; and the Ruddy Olive, Fig. 4, (_O. sanguinolenta_,) from _sanguis_—blood.
We must now bring our notice of the Univalves to a conclusion; there are several genera, and many very curious and beautiful species which we have been unable to notice at all, and of those which we have, a short account only could be given; sufficient however, as we trust, to interest our readers in the subject, and induce them to continue the study of it into larger works. Before leaving this division of shells, we would call their attention to one of its greatest ornaments, that is the Ventricose Harp Shell, (_Harpa ventricosa_,) from the Latin _ventriculus_—the stomach, applied to this shell on account of its swelled or inflated shape. Nothing, however, can be more elegant than the whole form, nor more beautiful than the markings of this lovely species, (see Plate VI, Fig. 5,) which belongs properly to the Whelk family.
COWRIES.
Of Cowries we have already spoken in our chapter on the Uses of Shells, they are among the commonest of our testaceous ornaments, and are remarkable, especially the foreign kinds, for richness and diversity of colour, and the high polish which they bear. The native species are small plain shells, commonly called Pigs, from some real or fancied resemblance which they bear to the swine; they are pretty little white-ribbed shells, and are tolerably plentiful on various parts of the British coasts. There are three kinds, namely, the Louse Pig, or Nun Cowry, the Flesh-coloured, and European Pig Cowries. The first of these is of a pale reddish colour, with six square black spots on the back; the second is a beautiful rose tint; and the third is ash-coloured or pinkish, with three black dots, and a white streak down the back. The Money Cowry, (_Cypræa moneta_,) used as current coin in many parts of India, as well as on the coast of Guinea, is a yellow and white shell, with a single band of the former colour; it is small of size, and is sometimes called the Trussed Chicken, for the same reason as the term Pigs is applied to its British relatives. These Cowries are obtained principally about the Phillippine Islands, the Maldive Islands, and the coast of Congo, where, after high tides, the women collect them in baskets mixed with sand, from which they are afterwards separated and cleaned, when they are ready for the market.
They are only useful as coin so long as they remain unbroken. The value of a single shell is very small, as the following table will shew:—Four Cowries make one gunder; twenty Gunders one punn; four Punns one anna; four Annas one cahaun; and four Cahauns one rupee. The value of the latter coin is equal to two shillings and threepence, English money, and this would be exchangeable for five thousand one hundred and twenty Cowries; so that it would never do to pay large sums in this kind of coin: a waggon would be required to convey a few pounds with. In this country the Money Cowries are frequently used as markers or counters in social games; they are generally white, in shape rather broad and flat, being much spread out round the edges, which are slightly puckered, like frills. Here are two figures of the shell, exhibiting the back and front view.
[Illustration]
On Plate VII, will be found a group of other Foreign Cowries, most of which will be recognized as familiar ornaments of the mantel and side-board. Fig. 1 is the Spotted or Leopard Cowry, sometimes also called the Tiger Cowry, (_C. tigris_,) which, in the earlier stages of its growth, is simply marked with broad bands of lighter colour across the shell. Fig. 2, the Map Cowry, (_C. mappa_,) curiously marked and shaded, so as to resemble a coloured map; there are several varieties of this beautiful shell, such as the rosy and dark variety from the Pearl Islands, in the Indian Ocean; the Citron and Dwarf Rich-mouthed variety, from the Mauritius. Fig. 3, the Mole Cowry, (_C. talpa_,) the last word being the Latin for a mole, is of a more slender form than most other species of the _Cypræidæ_ family, so called on account of their beauty, _Cyprea_ being a name of Venus, the goddess of beauty. Any one who has seen a mole, must be struck with the resemblance of its general outline to this shell, of which there is a darker-coloured variety of somewhat stouter form, called _exustus_—burned or scorched. Of the Poached-egg Cowries there are several species, the most common is called by naturalists _Ovulum ovum_, Fig. 4, from _ovum_—an egg; the back of this shell is much elevated and rounded; it is smooth and white; the inside is orange brown. Some of the Poached-egg group are of a more slender and angular shape, as, for instance, that called the Gibbous, (_O. Gibbosa_;) the moon when more than half-full, is called gibbous, that is rounded unequally, as this shell.
[Illustration]
Few shells undergo greater changes, both of shape and colour, during the process of growth, than the Cowries, which are called in France Porcelaines, on account of their high polish and brilliant hues; a single species in different stages of development, might well be, and often is, taken for distinct shells. Much might be said about the Mollusks which inhabit them, but our present subject has rather to do with their outer covering than their internal structure. The most rare and valuable, if not the most beautiful of these Cowries, is the _C. aurora_, or _aurantium_, Morning-dawn, or Orange Cowry, a perfect specimen of which has been sold for fifty guineas. There is a very curious shell called the Common Weaver’s Shuttle, (_Oculum volva_,) generally included in the _Cyprea_ family; of this a representation will be found on Plate VII, Fig. 5. This is brought from China.
BIVALVES.
Acephalous Mollusks, with Bivalve Shells, is the name given by modern naturalists to the class of animals of which we have now to speak; the only one of these terms which will require explanation is the first; it comes from the Greek, and means headless, so an Acephalan is a molluscous animal without a head, as
THE OYSTER,
Which may be considered as the King of Bivalves; his palace, to be sure, is somewhat rough and rugged outside, but within, its walls are smooth and polished, lustrous and iridescent, and altogether beautiful; of a nacrous or pearly appearance, now flushing into a rose tint, now fading into pure white, and adorned sometimes with goodly pearls of price; truly this monarch of the _Conchifers_ has a habitation worthy of a prince, wherein he lives in right royal state. Our readers may smile perhaps at the idea of the solitary Oyster doing this, down there on his mud bank or rocky anchorage ground, shut up in his dirty-looking shells, and holding, as it seems, commune with no one, not even his fellow mollusks; how can he be said to live in royal state, or indeed any state at all, except in a most weary, stale, flat, and unprofitable one? And this only shews how erroneously those often judge who do so hastily, and from first appearances.
If we take a peep through a microscope, under the direction of a naturalist named Rymer Jones, we shall see that “the shell of an Oyster is a world occupied by an innumerable quantity of animals, compared to which the Oyster itself is a colossus. The liquid enclosed between the shell of the Oyster contains a multitude of embryos, covered with transparent scales, which swim with ease; a hundred and twenty of these embryos, placed side by side, would make an inch in breadth. This liquid contains besides, a great variety of animalculæ, five hundred times less in size, which give out a phosphoric light. Yet these are not the only inhabitants of this dwelling—there are also three distinct species of worms.”
Let us see if there are any hard names here that want explaining before we go any further. The first we stumble upon is _Colossus_, which comes from the Latin, and means a great image or statue, like that which ancient historians tell us once bestrode the entrance to the harbour of Rhodes. _Embryo_ comes from the Greek, and means something small and unfinished, that is to expand or grow into a more perfect form, as the seed into a plant. _Animalculæ_, are minute or very small animals, such as cannot be distinguished without the help of a microscope, hence they are sometimes called microscopic animals; this word comes from the Latin _animalis_, which means having life. _Phosphoric_ signifies luminous, or giving out light. The Greek name of the morning star is _Phospha_. In Latin, _Phosphorus_ is a term applied to a substance which chemists extract from bones and other animal matter, and which, when exposed to air, burns with a pale blue light, like that emitted by the glow-worm. Many of the oceanic or sea animalculæ are exceedingly phosphorescent, so that by night, the waves appear like billows of flame. Of this luminosity of the ocean, as it is termed, we shall have to speak on another occasion. We will now return to the Oyster, who, it will be seen, is by no means so solitary in his bivalve palace as might be supposed. He has his torch-bearers, and other attendants, quite a host of them, no doubt magnificently dressed, if we could but see them to advantage, and well instructed in the several duties which they have to perform. Oh yes, certainly, as the Irish poet has said,
“Of all the Conchiferous shell-fish, The Oyster _is_ surely the King;”
Shall we continue the quotation? and say
“Arrah Mick, call the people who sell fish, And tell them a dozen to bring: For it’s I that intend to demonstrate, The creature’s phenomena strange, Its functions to set every one straight, And exhibit their structure and range.”
Scarcely will our limited space permit us to do this, but a few of the most remarkable particulars about this common Acephalan, we feel called upon to set before our readers.
First, then, it belongs to the class _Conchifera_; this is a word which we must stop to examine a little; it seems to come from the Latin _concha_, which means a shell-fish with two shells, in other words a bivalve mollusk. Second, our Oyster belongs to the class _Pectinidæ_. Now _pecten_ is the Latin for a comb, and this class includes those bivalve shells whose edges are toothed, or, as it is said, _pectinated_; in the scallop and the cockle shells this peculiarity is more observable than in those of other members of the class, and these form the typical, or so to speak, pattern genus, _pecten_. Thirdly, the Common Oyster is a _Monomyarian Conchifer_. Ah! that’s something like a name for the acephaloid monarch! Look at these two words, _mono-myarian_, _di-myarian_, you know of course that mony-syllable means one syllable, and dis-syllable means two. You sometimes hear of a person who leads a _monotonous_ life, and you think perhaps of the Oyster shut up in his shell all alone, _one_ by himself; this notion you now know to be a false one; although it is true that he has but one abductor muscle, and therefore belongs to the division of the _Pectinidæ_ family called _Monomyaria_, while the Pearl Oyster has two, and therefore belongs to that termed _Dimyaria_. If, as they say, there is reason in the roasting of eggs, surely there must be in the names given to the classes and divisions of shells. We hope to have succeeded in making the why and the wherefore in this case somewhat plain;—_one_—_two_—and away we go out of this maze of hard names. But what about the abductor muscle, above spoken of? well, this must be explained; _abduce_, coming from the Latin _abduco_, means to separate, to draw away, hence we have _abduction_. During the life of an Oyster, the usual and natural state of the shell is that of being kept open for a little distance, to allow the water necessary for its nourishment and respiration to flow in and out; but as a security against danger, it was necessary to furnish the animal with the means of rapidly closing the shell, and retaining the valves in a closed state. These actions being only occasional, yet requiring considerable force, are effected by means of a muscular power, for which purpose one or two, or sometimes more strong muscles are placed between the valves, their fibres passing directly across from the inner surface of one to that of the other, and firmly attached to both, and these are called the abductor muscles, because their office is to draw or pull; how strongly they do this those whose business it is to open Oysters can best tell; if the animal within were not alive, the process would not be a difficult one, as in that case the muscles would be relaxed, and the shell would come open of itself, so that actually people who eat Oysters directly they are opened, swallow them “all alive-O!”