Chapter XII: ACEPHALOUS MOLLUSCA--continued (1)

MYTILIDÆ--THE MUSSEL.

"Ecce inter virides jactatur mytilus algas."

_Anthologia._

We shall now consider the nineteenth family or Mytilidæ, which includes Mytilus, Modiola, Lithodomus, and Dreissena.

The well-known shell of the mussel (Fig. 157, _Mytilus edulis_) is longitudinal, equivalve, and regular, pointed at the base, with capacity to attach itself by a byssus; the hinge has no teeth, but a deep furrow, in which the ligament is located. In the genus _Mytilus_ the byssus is divided to its base. In _Modiola_ it has a common corneous centre. In _Pinna_ the anus is furnished with a long angular base. In all these genera the foot is small, its retractile muscles numerous, and the byssus large. In _Lithodomus_ the byssus is rudimentary; the muscles are retractile, equal, and two pairs only. In _Unio_, _Cardium_, and _Hyria_, the foot is large and not byssiferous.

The animal, as described by M. Chenu, is elongate, oval, the lobes of the mantle simple or fringed, divided at the edge into two leaves, the interior being very short, bearing a fringe of small, cylindrical, and movable fillets; the exterior leaf is united to the shell very near the edge. The opening by which water and food are introduced supplies the branchiæ at the same time. The stomach consists of a white membrane, thin, like opaline, and presenting itself in longitudinal folds; the liver is granulous, composed of greenish grains more or less deep, contained in the meshes of a whitish tissue forming a thickish bed, which surrounds the stomach, the intestines taking the direction of the median and dorsal line, and beneath the heart are received and terminate in a small appendage, floating in the cavity of the mantle near the hinge. The foot is, perhaps, the remarkable organ of the mussel: it is small, semi-lunar when not in motion, but capable of great elongation, resembling thus a sort of conical tongue, having a longitudinal furrow on its side. It is put in motion by several pairs of muscles, all of which penetrate and are interlaced with the tissue; behind it is the silky byssus. The mouth is large, and furnished with two pairs of soft palpi, which are pointed and fixed by their summit. Abdominal masses emanate, and on each side a pair of nearly equal branchiæ. The additional muscles, one anterior and small, the other posterior, large, and rounded. At the base of the foot is a gland which furnishes a viscous secretion; this viscous liquid is organized and moulded in the groove of the foot, and forms a thread, and originates the byssus; it is a bundle of hairs, mane, or thread, which holds on to its shell.

The byssus plays an important part in the organization of the mussel. While the oyster remains eternally riveted to its rock, until torn from it by violence, the mussel moves about, and in this motion the byssus is an active agent. The mussel attaches its byssus to some fixed object, and drawing upon it, as upon a line, the shell is displaced. The house is drawn onwards; the animal is in motion. It takes no great strides, but a fraction of an inch satisfies its desires; it is, however, an advance upon the oyster, and a lesson in mechanics. The mussel stretches out its foot, and, at the point chosen, it hooks on a hair of the byssus; then, withdrawing the foot suddenly, and hauling on the thread, the animal and shell are moved forward. Every time it repeats this motion it seems to attach an additional hair, so that at the end of the four and twenty hours it has used many inches in length of cordage. In the byssus of some mussels we find as many as a hundred and fifty of these small threads, with which the animal anchors itself most securely to the rock. Aided by this cordage, the mussel suspends itself to vertical rocks, holding on a little above the surface of the water, so that the shell is smooth and polished as compared with the coarse and rugged shell of the oyster.

The mussels, like the oysters, are gregarious, and widely diffused over all European seas. They abound on both sides the Channel, their lower price having procured for them the name of "the poor man's oyster;" but it is infinitely less digestible and savoury than its congener.

A, right lobe of the mantle; D, rectum; G, branchiæ; H, foot; J, posterior muscle; L, superior tube; O, heart; P, ventricle; Q, auricle; X, pericardium; _b_, tentacles; _d_, byssus; _e_, gland of the byssus; _g_, retractile muscle of the foot; _h_, valves of the mantle; _i_, oviduct; _j_, orifice of the excretory organ; _k_, internal ditto.]

Many of our readers may think that mussels are found on the shore in a state of nature, of good size, well flavoured, and fit for the table. Nothing of the kind! Detached from the rocks and cliffs of the sea, where it has been growing in a natural state, it is lean, small, acrid, and unwholesome food; and it is only when human industry intervenes to ameliorate this child of Nature that it becomes palatable and wholesome food. In order to trace the ameliorative process by which the coriaceous flesh of the mussel was rendered tender, fat, and even savoury, we must conduct the reader back into the middle ages.

Some time in 1236 a barque, freighted with sheep and manned by three Irishmen, came to grief upon the rocks in the creek of Aiguillon, a few miles from Rochelle. The neighbouring fishermen who came to the relief of the crew succeeded with great difficulty in saving the life of the master, a man named Walton. Exiled upon the lonely shore of the Aunis, with a few sheep saved from shipwreck, Walton at first supported himself by hunting sea-fowl, which frequented the shore and neighbouring marshes in vast flocks. He was a skilful fowler, and invented or adapted a peculiar kind of net, which he called the _night net_. This consisted of a net some three or four hundred yards in length by three in breadth, which he placed horizontally, like a screen, along the quiet waters of the bay, retaining it in its position by means of posts driven into the muddy bottom. In the obscurity of the night the wild-fowl, in floating along the surface of the waters, would come in contact with the net, and get themselves entangled in its meshes.

But the Bay of Aiguillon was only a vast lake of mud, in which boats moved with difficulty; and Walton, having arranged his bird-net, began to consider what kind of boat would enable him most conveniently to navigate the sea of mud. The flat-bottomed, square-sided boat, known in our rivers as a _punt_, and on the Norman coast as an _acon_, was the result. Walton's boat had a wooden frame some three yards long and one in breadth and depth, the fore part of which sloped down into the water, in the form of a prow, at a slight angle. In propelling the boat the rower, who occupied the stern of the punt, knelt on his right knee (as represented in Fig. 159), inclining forward, with one hand on each edge, and the left leg outside the boat. A vigorous push with the left foot gave the frail boat an impulse, under which it rapidly traversed the bay from one point to the other.

The mussels swarmed in the little bay; and Walton soon remarked that they attached themselves by preference to that part of the post a little above the mud, and that those so placed soon became fatter, as well as more agreeable to the taste, than those buried in the mud. He saw in this peculiarity the elements of a sort of mussel culture which might become a new branch of industry. "The practices he introduced," says M. Coste, "were so happily adapted to the requirements of the new industry, that, after six centuries, they are still the rules by which the rich patrimony he created for a numerous population is governed. He seems to have applied himself to the enterprise, conscious not only of the service he was rendering to his contemporaries, but desirous that their descendants should remember him, for in every instance he has given to the apparatus which he invented the form of his initial letter W. After due consideration, Walton began to carry out his design. He planted a long range of piles along the low marshy shore, each pair forming a letter V, the front of the letter being towards the sea, and each limb diverging at an angle of forty-five degrees. These posts were driven about a yard asunder; they were about twelve feet long, six feet being above water, and interlaced with branches wattled together, so as to form continuous hurdles, each about two hundred yards long, which are called _bouchots_. By the assistance of this apparatus, which intercepted spat which would otherwise have been swept away to sea by the tide, Walton formed a magnificent collection of mussels; but he did not abandon his isolated piles. These, being without fascines or branches, and always submerged, arrested the spat at the moment of emission."

The advantages of this system of culture adopted by the Irish exile were so obvious that his neighbours along the shore were not slow to imitate his example. In a short time the whole bay was covered with similar bouchots. At the present time these lines of hurdles form a perfect forest in the little creek. About two hundred and thirty thousand piles support a hundred and twenty-five thousand fascines, which, according to M. Coste, "bend all the year under a harvest which a squadron of ships of the line would fail to float." There are about five hundred of these bouchots in the bay, each from two hundred to two hundred and fifty yards in length and six feet high.

The isolated piles are without palisades, and are uncovered only at spring tides. In the months of February and March the spat collected on them scarcely equals in size a grain of linseed; by the month of May it will be about the size of a split pea; in July, a small haricot bean: this is the moment for its transplantation. In this month the _bouchotiers_, as the men occupied in this culture are called, launch their punts and proceed to the part of the bay where these piles are driven. They detach with a hook the agglomerated masses of young mussels, which they gather in baskets, and carry them to their bouchots. These bouchots, that is to say, the piles covered with fascines and branches, are of four different heights, forming, so to speak, four stages, according to the age and growth of the mussel. Each stage receives the mollusc suitable to it. In the first stage of its existence the mussel cannot endure exposure to the air, and remains constantly under water, except at the period of spring tides. These are gathered in sacks made of old matting, or suspended in interstices of the basket-work. "These immense palisades," says M. Coste, "cover themselves with black clusters of mussels developed between the meshes of their tissues." At that time the second rows are cleared away to make room for younger generations; the mussels, which no longer dread the air, are transported to the more advanced bouchots, which remain above water in all tides, where they stay till they are fit for market, which usually happens after ten or twelve months of culture on the more advanced bouchots.

But, in order to prepare for this consummation, they are subjected to a second and even a third remove. There is no longer any danger in subjecting them to the air for many hours. From this they pass to a fourth stage, termed _Amont_ (Fig. 161). From this stage the full-grown mussel is removed. Under this system of culture the reproduction, nursing, collecting, and preparing for market, are made simultaneously. From July to January the mussel trade is in full operation, and the flesh in perfection. From February to April is the close season; their flesh is then poor and leathery. It is also remarked that those which inhabit the upper rows of the wicker-work are of a mellower flavour than those on the lower ranks, and that the intermediate rows are an improvement on those which are buried in the mud, although even these are preferable to mussels gathered on the sea shore in a state of nature.

M. Coste gives a graphic description of the manner in which this industry is carried on. "Having supplied the neighbouring villages," he says, "for the purpose of supplying the more distant cities, the bouchotiers land their punts, filled with mussels, which their wives carry into grottoes hollowed out of the cliffs; where they clean and pack them in hampers, baskets, and panniers, for conveyance by carts or pack-horses. They depart on their respective journeys at night, so as to reach their markets at La Rochelle, Rochefort, Surgéres, Saint-Jean-d'Angely, Angoulême, Niort, Poictiers, Tours, Angers, and Saumur, at an early hour. A hundred and forty horses and ninety carts make upwards of thirty-three thousand journeys annually to these cities. Besides this, forty or fifty boats come from Bordeaux, the isles of Ré and Oleron, and from the sands of Olonne, making an aggregate of seven hundred and fifty voyages per annum, distributing the harvest of the little bay at places where horses could not serve the purpose.

"A bouchot, well furnished, supplies annually, according to the length of its wings, from four to five hundred charges. The charge is a hundred and fifty kilogrammes (over three hundred pounds), and sells for five francs; a single bouchot thus carries a harvest equal in weight to a hundred and thirty to a hundred and forty thousand pounds, equal in value to £100; the whole bay probably yielding a gross revenue of £480,000. This figure, and the abundant harvest which produces it, gives only a slight idea of the alimentary resources of the sea shore; and every part of the coast, properly adapted for the purpose, could be turned to equal advantage. In the mean time, the Bay of Aiguillon remains a monument of what one man may accomplish."

While commending the mussel as an important article of food, we must not conceal the fact, that it has produced in certain persons very grave effects, showing that for them its flesh has the effects of poison. The symptoms, commonly observed two or three hours after the repast, are weakness or torpor, constriction of the throat and swelling of the head, accompanied by great thirst, nausea, frequent vomitings, and eruption of the skin and severe itching.

The cause of these attacks is not very well ascertained; they have in turn been ascribed to the presence of copper pyrites in the neighbourhood of the mussel; to certain small crabs which lodge themselves as parasites in the shell of the mussel; to the spawn of star-fishes or medusæ that the mussel may have swallowed. But, probably, the true cause of this kind of poisoning resides in the predisposition of individuals. The remedy is very simple: an emetic, accompanied by drinking plentifully of slightly acidulated beverages.

We have now come to the twentieth family, the Aviculidæ, which contains Avicula, Malleus, Maleagrina, Perna, and Pinna. The shells of the Hammerheads (_Malleus_) have a rough resemblance to the implement from which they derive their name. The valves are nearly equal, blackish, and somewhat wrinkled on the exterior, often brilliantly nacred in the interior. They are enlarged to the right and left of the hinge, forming prolongations on each side, which give them the fancied resemblance to the Hammerhead (Fig. 163). At the same time they grow in a direction opposite to the hinge, which gives something approaching the handle of the implement.

This is the first feature which a glance at _Malleus alba_ (Fig. 162) conveys. The hinge is without teeth, having instead a deep conical fossette or dimple, for the reception of a very strong ligament which acts upon the valves. The animal is contained in the interior of the shell, its mantle fringed by very small tentacular appendages. Only six actually living species of the genera are known, which are inhabitants of the Indian Ocean, of the Australian seas, and the Pacific Ocean.

The beautiful diaphanous nacre which embellishes the interior of so many ornamental cabinets are principally produced by the animal inhabiting the _Meleagrina_, a bivalve, sometimes designated the _pintadine_, or mother-of-pearl shell. This bivalve moors itself to the bottom of the sea by a strong byssus of a brownish colour. The door-posts of the shells are irregularly rounded in their young days; they are externally lightly foliated, and ornamented with bands of green and white, which spring from the summit in rays, and afterwards break off into two or three slightly scattered branches. In old age they become rugged and blackish. The shell is in its perfection when about eight or ten years old, their size being then about six inches in diameter, with a thickness of about an inch and a quarter.

Nacre is the hard and brilliant substance with which the valves of certain shells are lined in the interior. This substance is white, silky, slightly azure, and more or less iridescent. Most of the bivalves are supplied with nacre; some of them even yield a blue, or blue and violet pigment. The iridescent _Haliotis iris_, for instance, is an emerald-greenish blue of changing colour, with reflections of a purple violet. _Turbo argyrostomus_ (Linnæus) presents a mouth of bright silvery hue, while _Turbo chrysostomus_ appears in all the glory of gold; but the Pintadine yields the purest white nacre, as well as the most uniform, and especially the thickest. This product owes its brilliant and delicate appearance to the play of light on it in its highly-polished state. For practical purposes the nacre is separated from the shell with an instrument; sometimes all the exterior part of the shell being dissolved away from the precious substance, leaving only the naked bed of nacre.

Outside of the shell.
Inside of the shell.
]

But the most interesting of all the nacre-bearing shells is the pearl oyster (_Meleagrina margaritifera_), the exterior, as well as the interior, of which is represented in Fig. 164. The interior of the shell affords the most exquisite pearls; the Esterhazy collection of jewels afforded many such specimens. This shell is nearly round, and greenish in colour on the outside; it furnishes at once the finest pearls, under favourable circumstances, and the nacre so useful in many industrial arts. Fine pearls and nacre have, in short, the same origin. The nacre invests the whole interior of the shell of _Meleagrina margaritifera_; being the same secretion which in the pearl has assumed the globular form: in one state it is deposited as nacre on the walls of the bivalve, in the other as a pearl in the fleshy interior of the animal. This nacre is therefore at once a calcareous and horny matter, which the animal secretes, and which it attaches to the interior walls of the shell during the several periods of its development. Pearls are formed of the same substance, only in place of being deposited upon the valves in beds, the material is condensed and agglomerated in small spheroids, which develop themselves either on the surface of the valves or in the fleshy part of the mollusc. Between nacre and pearls, therefore, there is only the difference of the form of deposition. Fig. 165 represents the pearl oyster with calcareous concretions in various states of progress.

The finest pearls--solidified drops of dew, as the Orientals term them in the language of poetry--are secretions supposed to be the result of disease in the animal. The matter, in place of being spread over the surface of the valves in their beds, is condensed either on the centre of the valves or in the interior of the organ, and forms a more or less rounded body. The pearls, when deposited on the valves, are generally adherent; those which originate in the body of the animal are always free. Generally we find some small foreign body in their centre which has served as a nucleus to the concretion, the body being perhaps a sterile egg of the mollusc, the egg of a fish, a rounded animalcule, a grain of sand even, round which has been deposited in concentric layers the beautiful and much-prized gem.

The Chinese, and other Eastern nations, are said to turn this fact in the natural history of bivalves to practical use in making pearls and cameos. By introducing into the mantle of the mollusc, or into the interior of a living valve, a round grain of sand, glass, or metal, they induce a deposit which in time yields a pearl, in the one case free, and in the other adhering to the shell. In some cases they are said to be produced in whole chaplets by the insertion of grains of quartz connected by a string into the mantle of a species of _Symphynota_; in other cases, a dozen enamelled figures of Buddha seated have been produced by inserting small plates of embossed metal in the valves of the same species.

The pearls are very small at first; they increase by annual layers deposited on the original nucleus, their brilliancy and shade of colour varying with that of the nacre from which they are produced. Sometimes they are diaphanous, silky, lustrous, and more or less iridescent; occasionally they turn out dull, obscure, and even smoky.

* * * * *

The pearl oyster is met with in very different latitudes; they are found in the Persian Gulf, on the Arabian coast, and in Japan, in the American seas, and on the shores of California, and in the islands of the South Sea; but the most important fisheries are found in the Bay of Bengal, Ceylon, and other parts of the Indian Ocean. The Ceylon fisheries are under Government inspection, and each year, before the fisheries commence, an official inspection of the coast takes place. Sometimes the fishing is undertaken on account of the State, at other times it is let to parties of speculators. In 1804 the pearl fishery was granted to a capitalist for £120,000; but, to avoid impoverishing all the beds at once, the same part of the gulf is not fished every year.

The great fishery for mother-of-pearl Pintadines (_Meleagrina margaritifera_) takes place in the Gulf of Manaar, a large bay to the north-east of the island; it commences in the month of February or March, and continues thirty days, taken collectively, and occupies two hundred and fifty boats, which come from different parts of the coast; they reach the ground at daybreak, the time being indicated by a signal gun. Each boat's crew consists of twenty hands, and a negro. The rowers are ten in number. The divers divide themselves into two groups of five men each, who labour and rest alternately; they descend from forty to fifty feet, seventy being the very utmost they can accomplish, and eighty seconds the longest period the best divers can remain under water, the ordinary period being only thirty seconds. In order to accelerate their descent, a large stone is attached to a rope. According to travellers the oars are used to rig out a stage, across which planks are laid over both sides of the boat; to this stage the diving-stone is suspended. This stone is in the form of a pyramid, weighing about half-a-hundredweight; the cord which sustains it sometimes carries in its lower parts a sort of stirrup to receive the foot of the diver. At the moment of his descent he places his right foot in this stirrup, or, where there is no such provision, he rests it on the stone with the cord between his toes. In his left foot he holds the net which is to receive the bivalves; then, seizing with his right hand a signal-cord conveniently arranged for his purpose, and pressing his nostrils with the left hand, he dives, holding himself vertically, and balancing himself over his foot.

Each diver is naked, except the band of calico which surrounds the loins. Having reached the bottom, he withdraws his foot from the stone, which ascends immediately to the stage. The diver throws himself on his face, and begins to gather all the pintadines within his reach, placing them in his net. When he wishes to ascend he pulls the signal cord, and is drawn up with all possible expedition.

A good diver, we have said, seldom remains more than thirty seconds under water at one time; but he repeats the operation three or four, and, in favourable circumstances, even fifteen or twenty times. The labour is extremely severe. On returning to the boat they sometimes discharge water tinged with blood by the mouth, nose, and ears. They are also exposed to great danger from sharks, which lie in wait for and frequently devour the unhappy divers.

They continue to fish till mid-day, when a second gun gives the signal to cease. The proprietors wait on shore for their boats, in order to superintend their discharge, which must take place before night sets in, in order to prevent concealment and robbery.

In past times the Ceylon fisheries were very valuable. In 1797 they are said to have produced £144,000, and in 1798 as much as £192,000. In 1802 the fisheries were farmed for £120,000; but for many years the banks have been less productive, and are now said to yield only the sum of £20,000 per annum.

The natives of the Bay of Bengal, those of the Chinese coast, of Japan, and the Indian Archipelago, all abandon themselves to the pearl fishery, the produce being estimated to realize at least £800,000. Fisheries analogous to those of Ceylon take place on the Persian coast, on the Arabian Gulf, along the coast of Muscat, and in the Red Sea.

In these countries the pearl fishing does not commence till the months of July and August, the sea being at that time calmer than in other months of the year. Arrived on their fishing-ground, the fishermen range their barques at a proper distance from each other, and cast anchor in water from eight to nine fathoms deep. The process is pursued here in a very simple manner. When about to descend the divers pass a cord, the extremity of which communicates with a bell placed in the barque, under the armpits; they put cotton in their ears, and press the nostrils together with a piece of wood or horn; they close their mouths hermetically, attach a heavy stone to their feet, and at once sink to the bottom of the sea, where they gather indiscriminately all shells within their reach, which they throw into a bag suspended round the haunches. When they require to breathe they sound the bell, and immediately they are assisted in their ascent.

On the oyster-banks off the Isle of Bahrein the pearl fishery produces about £240,000; and if we add to this the addition furnished by the other fisheries of the neighbourhood, the sum total yielded by the Arabian coast would probably not fall short of £350,000.

In South America similar fisheries exist. Before the Mexican conquest the pearl fisheries were located between Acapulco and the Gulf of Tehuantepec; subsequently they were established round the Islands of Cubagua, Margarita, and Panama. The results became so full of promise that populous cities were not slow to raise themselves round these several places.

Under the reign of Charles V., America sent to Spain pearls valued at £160,000; in the present day they are estimated to be worth £60,000. In the places mentioned, the divers descend into the sea quite naked; they remain there from twenty-five to thirty seconds, during which space they can only secure two or three pintadines. They dive in this way a dozen times in succession, which gives an average of between thirty and forty bivalves to each diver.

* * * * *

The bivalve is carried on shore, and piled up on mats of Espartero grass. The mollusc dies, and soon becomes decomposed; it requires ten days to be thoroughly disorganized. When in a thoroughly corrupt state, they are thrown into reservoirs of sea-water, when they are opened, washed, and handed over to the dealers. The valves furnish _nacre_, and the parenchyma the _pearls_.

The valves are cleansed, and piled up in tuns or casks; by raising their external surface plates of nacre are obtained more or less thick, according to the age of the mollusc.

Nacre of three kinds are distinguishable in commerce: silver-faced, bastard white, and bastard black. The first are sold in cases of two hundred and fifty to two hundred and eighty pounds; they are brought from the Indies, from China, and Peru. The ships of various nations import these shells as ballast. The second is delivered in casks of two hundred and fifty pounds weight; it is a yellowish white, and sometimes greenish; sometimes red, blue, and green.

* * * * *

Pearls form by far the most important product of the animal. When they are adherent to the valves they are detached with pincers; but, habitually, they are found in the parenchyma of the animal. In this case the substance is boiled, and afterwards sifted, in order to obtain the most minute of the pearls; for those of considerable size are sometimes overlooked in the first operation. Months after the mollusc is putrified, miserable Indians may be observed busying themselves with the corrupt mass, in search of small pearls which may have been overlooked by the workmen.

The pearls adherent to the valve are more or less irregular in their shape; they are sold by weight. Those found in the body of the animal, and isolated, are called _virgin pearls_, or _paragons_. They are globular, ovoid, or pyriform, and are sold by the individual pearl. In cleaning them, they are gathered together in a heap in a bag and worked with powdered nacre, in order to render them perfectly pure in colour and round in shape, and give them a polish; finally, they are passed through a series of copper sieves, in order to size them. These sieves, to the number of twelve, are made so as to be inserted one within the other, each being pierced with holes, which determine the size of the pearl and the commercial number which is to distinguish it. Thus, the sieve No. 20 is pierced with twenty holes, No. 50 with fifty holes, and so on up to No. 1000, which is pierced with that number of holes. The pearls which are retained in Nos. 20 to 80, said to be _mill_, are pearls of the first order. Those which pass and are retained between Nos. 100 to 800 are _vivadoe_, or pearls of the second order; and those which pass through all the others and are retained in No. 1000 belong to the class _tool_, or seed pearls, and are of the third order.

They are afterwards threaded; the small and medium-sized pearls on white or blue silk, arranged in rows, and tied with ribbon into a top-knot of blue or red silk, in which condition they are exposed for sale in rows, assorted according to their colours and quality. The small or seed pearls are sold by measure or weight.

In America the bivalve is opened with a knife, like the common edible oyster, and the pearl is obtained by breaking up the mollusc between the finger and thumb without waiting for its decomposition; nor is it boiled. This is a much longer and less certain process than that pursued in the East; but the pearls are preserved in greater freshness by the process--for the nacre of the dead shells is less brilliant than that of those which have been suddenly killed, and at once separated from the soft parts.

* * * * *

Some few pearls have become historical, from their size and beauty. A pearl from Panama, in the form of a pear, and about the size of a pigeon's egg, was presented in 1579 to Philip II., King of Spain: it was valued at £4000. A Lady of Madrid possessed an American pearl in 1605 valued at 31,000 ducats.

The Pope Leo X. purchased a pearl of a Venetian jeweller for £14,000. Another was presented to the Sultan Soliman the Great by the Venetian Republic valued at £16,000. Julius Cæsar, who was a great admirer of pearls, presented one to Servilia which was valued at a million of sesterces, about £48,000 of our money.

There is no data for the volume or value of the two famous pearls of Cleopatra; one of these which the queen is said to have capriciously dissolved in vinegar and drank--Heavens preserve us from such a draught!--is said by some authors to have been worth £60,000; the other was divided into two parts, and suspended one half from each ear of the Capitoline Venus. Another pearl was purchased at Califa by the traveller Tavernier, and is said to have been sold by him to the Shah of Persia for the enormous price of £180,000.

A prince of Muscat possessed a pearl so extremely valuable--not on account of its size, for it was only twelve carats, but because it was so clear and transparent that daylight was seen through it--he refused £4000 for it.

In the Zozema Museum at Moscow there is a pearl, called the "Pilgrim," which is quite diaphanous; it is globular in form, and weighs nearly twenty-four carats. It is said that the pearl in the crown of Rudolph II. weighed thirty carats, and was as large as a pear. This size, besides being indefinite, is more than doubtful.

The shahs of Persia actually possess a string of pearls, each individual of which is nearly the size of a hazel nut. The value of this string of jewels is inestimable.

At the Paris Exposition of 1855, Her Majesty the Queen exhibited some magnificent pearls; and on the same occasion the Emperor of the French exhibited a collection of 408 pearls, each weighing over nine pennyweights, all of perfect form and of the finest water. The Romans were passionately fond of pearls, and they have transmitted their taste to the Eastern nations, who attach notions of great grandeur and wealth to the possessor of large and brilliant pearls.

* * * * *

The genus _Pinna_, so called by Linnæus, from one of the species which was so designated from the resemblance of its byssus to the aigrette or plumelet which the Roman soldiers attached to the helmet. French naturalists name them _jambonneau_, from their singular resemblance to a dried ham (Figs. 166 and 167), their brown, smoky colour not a little aiding the resemblance. This shell is fibrous, horny, very thin and fragile, compressed, regular, and equivalve, triangularly pointed in front, round or truncated behind. The hinge is linear, straight, and without teeth; the ligament, in great part internal, occupies more than half the anterior half of the dorsal edge of the shell, forming a straight elongated fossette.

The animal is thick, elongated, with mantle open behind, presenting a conical furrowed foot, hearing a considerable byssus.

The _Pinnæ_ are found in almost every sea, and at various depths; they are constantly attached by their byssus, and in a vertical position, the larger side of their shell being uppermost. They assemble on sandy bottoms in considerable numbers. The byssus has in all ages fixed the attention of the Mediterranean fishermen upon these curious shells. With its tuft of fine silky hairs, six or seven inches in length, of a fine reddish-brown hue, articles of luxury are formed, which are often mentioned by the Latin writers. The threads of the byssus, which are remarkable for their unalterable colour, were formed by both Greeks and Romans into a fabric to which there is nothing analogous in the world. The Maltese and Neapolitans still fashion soft tissues from it, but the stuffs so manufactured are pure objects of curiosity.

Twelve species are described as living in the several seas. _Pinna nobilis_ (Fig. 169), the byssus of which was employed in the ancient Neapolitan industry, inhabits the shores of the Mediterranean. _Pinna bullata_, Swainson (Fig. 168), is also a well-known species.

OSTREIDÆ.

Our twenty-first family, Ostreidæ, contains Lima, Spondylus, Pecten, Anomia, and the all-important oyster. The common oyster, _Ostrea edulis_, is found in all seas. It is unequally valved, modified in shape by the form of the submarine body to which it happens to be attached. The lower or adherent valve is concave, always the largest; the upper one thin, usually flat; the shell is lamellar, rough externally, and seems to be composed of broken layers, adhering slightly to each other, as if the successive layers had been built up from within, and each succeeding layer was an enlargement upon its predecessor. The hinge which unites the valves is an elastic toothless ligament placed behind the centre, which opens the valves.

The interior surface of the valves is smooth and white, diaphanous or pearly towards the centre, but near the back an oval or rounded impression may be observed, to which a thick and whitish fleshy body is attached. This is the central muscle which draws the valves together, hermetically closing them upon the animal. This muscle is cut through in the process of opening the oyster.

The animal has no power of locomotion; its foot is very small and often wanting, no syphon, but lies with its mouth open, and slightly attached to the shell. The shell itself is always adherent, as if soldered to the rock or other submarine body, the point of adherence being near the summit of the lower valve, at the part called the _heel_.

Let us suppose the oyster opened by the double dissection of the ligament of the central muscle and of the abductor valves. When displayed before our eyes, we see in the bottom of the shell a flattened, shapeless animal, semi-transparent, greyish, and somewhat oval-shaped. The gastronomist, who seldom sees beyond his nose, thinks that in spite of its culinary merits the oyster belongs to the lowest rank of animal existence; but he deceives himself, and does not know how complex and delicate is the organization of the humble bivalve. The animal is enveloped in a sort of smooth, thin, contractile tissue called the _mantle_, which folds round it, presenting two lobes, separated on the greatest part of its circumference, and forming a sort of hood, the summit of which abuts upon the hinge of the bivalve. The edges of this mantle are fringed with very small cilia, which the creature can extend and draw back at pleasure, and which seem to be gifted with a certain amount of sensibility. It is this mantle which secretes and deposits the calcareous matter which forms the shell, each plate of which is an enlargement on the preceding one, until it constitutes a pyramid of thin convex lamellæ.

At the point where the lobes of the mantle meet, near the summit of the valve, is the mouth of the animal, with its thin membranous lips. This organ is large and dilatable, and is accompanied by four flat triangular pieces, by means of which the animal introduces its food into the stomachal cavity.

A very short gullet is attached to the mouth, which leads to a pear-shaped stomach. After this stomach comes a slender sinuous intestine, which, leading obliquely towards the interior, descends a little, then reascends, passes behind the stomachal cavity, nearly on a level with the mouth, crossing its first path in order to reach the posterior face of the adductor muscle, in the centre of which it terminates with a free opening. The stomach and intestines are surrounded on all sides by the liver, which alone constitutes a notable portion of the mass of organs. This liver is of a blackish colour, pervaded with a deep yellow liquid, which is the bile. Thus the stomach and intestines of the oyster are surrounded by the _liver_; the mouth is connected with the stomach, and the intestines open in the back.

The heart of the oyster is placed under the liver, and is surrounded closely by the terminal part of the intestines. It is composed, like the same organ in the superior animal, of two distinct cavities, an auricle and ventricle. From the ventricle issues a vessel, which is divided into three distinct canals. One of these carries the blood towards the mouth and tentacles; another carries it towards the liver; the last distributes the nourishing fluid to the rest of the body. The blood of the oyster is limpid and colourless; it passes successively from the auricle of the heart, where it is vivified, into the ventricle, and from this last cavity into the great vessel of which we spoke, which distributes it into the interior of the animal.

The oyster thus possesses a true circulation; not that double system which characterises the mammals, and which includes arterial and pulmonary action, but a simple circulation, as it exists in fishes and many other animals. It breathes also in the bottom of the water, after the manner of fishes, being, like the fish, provided with organs called gills or _branchiæ_, whose function is to separate the oxygen dissolved in the water from its other ingredients; these branchiæ, which are placed under the mantle, consist of a double series of very delicate canals, placed close together, not unlike the teeth of a fine comb.

Having no head, the oyster can have no brain; the nerves originate near the mouth, where a great ganglion is visible, whence issues a pair of nerves which distribute themselves in the regions of the stomach and liver, terminating in a second ganglion, situated behind the liver. The first nervous branch distributes its sensibility to the mouth and tentacles; the second, to the respiratory branchiæ.

With organs of the senses oysters are unprovided. Condemned to a sedentary life, riveted to a rock where they have been rooted, as it were, in their infancy, they neither see nor hear; touch appears to be their only sense, and that is placed in the tentacles of the mouth.

The mode of reproduction in these creatures is very peculiar. The oyster unites in itself the functions of both sexes. In the same organ are found the eggs--called _spat_--and the mobile corpuscles intended to fertilize them.

The eggs are yellowish in colour, and exist in prodigious numbers in each individual. We are assured that an oyster may carry as many as two millions of eggs! Nature always makes ample provision for the preservation of species; but in spite of the most ample provision here displayed, man, in his reckless and wasteful gluttony, has all but defeated Nature. A tyro can compute how many individuals a bank of oysters reckoned at twenty thousand would produce, at the rate of two millions, or eight hundred thousand, as other authorities assert, from each one annually, and it will amount to an incredible number--in fact, each would multiply itself by millions in three years; and yet, thanks to our improvident management, they get scarcer every year.

The spawning season is usually from the month of June to the end of September: during this season the oysters deposit their eggs in the folds of the mantle. During the period of incubation the eggs remain surrounded by mucous matter, which is necessary to their development, the whole having the appearance of a thick cream--this milky appearance being due to the accumulated mass of ova surrounded by the mucus: this mass undergoes various changes of colour while losing its fluidity, becoming successively yellowish, greyish, brown, and violet, a condition which indicates the near termination of the embryo state, for the oysters do not, like many other inhabitants of the sea, leave their ova; they incubate them in the folds of their mantle, and only discharge them when they can live without the maternal protection. Nothing is more curious to witness than a bank of oysters at the spawning season. Every adult individual of which it is composed throws out its phalanx of progeny. A living dust is seen to exhale from the oyster bank, troubling the water and giving it a thick cloudy appearance, which disseminates itself little by little in the liquid, until it dissipates and loses itself far from its focus of production. The _spat_ is soon scattered far and wide by the waves; and unless the young oyster finds some solid body to which it can attach itself, it falls an inevitable victim to the larger animals which prey upon it. In this its infant state, when it has just left the protection of the parent shell, the microscope reveals the young bivalve, with its shell perfect, having an apparatus which is also a swimming _pad_, ready to adhere to the first solid body which the current drives it against. This pad or cushion (which is represented in Fig. 170) is furnished with vibratile cilia, disposed round the young shell. Aided by the powerful adductor muscles, with which it is also provided, this cushion is projected through the water at the will of the young inhabitant, which has every facility for the purpose: it is even said to swim about near the mother, before final dismissal from the maternal protection, seeking shelter at the least alarm between the valves of the parent shell. The pad disappears after the young oyster has finally attached itself to a permanent bed of its own.

Before this period of its life arrives, however, many are the dangers to which it is exposed: its enemies are numerous; they lie in ambush for it in every cranny! It has to guard itself against eddies and currents, which would drive it out to sea, and mud banks, in which it would be smothered. Crustaceans, worms, and polyps, with other equally voracious marine inhabitants, prey upon it. Last, but not least, come the terrible and multiplied engines of the eager fisherman--and we readily comprehend why the oyster is provided with such accumulated masses of ova.

If the young bivalve is fortunate enough to escape all the snares and dangers we have enumerated, it grows rapidly. It is quite microscopic at the period of its discharge from the parent shell; at one month it is of the size of a large pea, at the end of six months it is about three-quarters of an inch, a year after its birth an inch and a half to two inches, and finally, at the end of three years it has become merchandise; that is to say, it is in a state to be sent to the parks for preservation and feeding. In Fig. 171 we see a group of oysters,[9] of various ages, attached to a piece of wood: A being oysters of twelve to fifteen months, B five or six months, C three to four months, D one to two months, and E oysters twenty days after birth.

The species of oysters usually eaten are the common oyster (_Ostrea edulis_, Linn.) of our own coasts and the opposite shore, and the horsefoot oyster (_O. hippopus_, Linn.). On the Mediterranean coast are the rose-coloured oyster (_O. rosacea_, Favanue), and the milky oyster (_O. lacteola_, Moquin-Tandon), besides the small and little-known crested oyster (_O. cristata_, Born), and the folded oyster (_O. plicata_, Chemnitz). On the Corsican coast is the oyster called foliate (_O. lamellosa_, Brocchi).

There are two principal varieties of the common oyster dredged on the French coast, which differ in size and delicacy of flavour. These are the Cancale and Ostend oyster. When the first has been fed for some time in the oyster park, and has assumed its greenish hue, it is designated the Marenna oyster, from "the park" so named in the Bay of Seudre. Of this green colour we shall speak elsewhere.

Who believed Uncle Jack when he told us in our youth of oysters growing on trees, and oysters so large that they required to be carved like a round of beef--of oysters on the Coromandel coast as large as soup-plates? Nevertheless Uncle Jack's stories were true: there are oysters which require carving, and oysters have been plucked off trees. In some parts of America they grow very large. Virginia possesses nearly two million acres of oyster-beds. The sea-board of Georgia is famed for its immense supplies; the whole coast of Long Island, extending to a hundred and fifteen miles, is occupied with them, and all over the States evidence is to be seen of the estimate in which the favoured bivalve is held by the American people.

Natural oyster-beds are found in bays, estuaries, and other sheltered sinuosities of the coast, with shelving and not too rocky bottoms, such places being, according to the natural law of production, favourable for the increase of the colony. Such banks abound in every sea. In France the oyster-beds of Rochelle, of Rochefort, the Isles of Ré and Oleron, the Bay of St. Brieuc, of Cancale, and Granville, are famous for the quality of their produce.

On the Danish coast there are from forty to fifty oyster-banks, situated on the west coast of Schleswig; the best bed lying between the small isles of Sylt, Amron, Fohr, Pelworm, and Nordstrand. At the point of Jutland, and opposite Shagen, beds less productive are found.

The great oyster-beds of England extend from Gravesend, in the estuary of the Thames and Medway, along the Kentish coast on the one hand, and the estuary of the Colne and other rivers on the Essex coast. The Frith of Forth is also famous for its oyster-beds, extending from Preston Pans far up the estuary of the river; but, curiously enough, all these great banks, without exception, have been impoverished, and all but exhausted, by improvident dredging, in spite of the "close season" which has always existed.[10]

* * * * *

"He was a bold man who first ate an oyster," has been said before. The name of the courageous individual has not been recorded, but Mr. Bertram, in his "Harvest of the Sea," tells us a legend concerning him: "Once upon a time,"--it must have been a long time ago,--"a man of melancholy mood was walking by the shores of a picturesque estuary, listening to the monotonous murmur of the sad sea-waves, when he espied a very old and ugly oyster-shell all coated over with parasites and sea-weeds. It was so unprepossessing that he kicked it with his foot, and the animal, astonished at receiving such rude treatment on its own domain, gaped wide with indignation, preparatory to closing its bivalve still more tightly. Seeing the beautiful cream-coloured layers that shone within the shelly covering, and fancying that the interior of the shell itself must be beautiful, he lifted up the aged 'native' for further examination, inserting his finger and thumb within the valves. The irate mollusc, thinking, no doubt, that this was meant as a further insult, snapped its pearly door down upon his finger, causing him considerable pain. After releasing his wounded digit, our inquisitive gentleman very naturally put it in his mouth. 'Delightful!' exclaimed he, opening wide his eyes; 'what is this?' and again he sucked his finger. Then the great truth flashed upon him that he had found out a new delight--had, in fact, achieved the most important discovery ever made. He proceeded at once to realize the thought. With a stone he opened the oyster's stronghold, and gingerly tried a piece of the mollusc itself. 'Delicious!' he exclaimed; and there and then, with no other condiment than its own juice, with no accompaniment of foaming brown stout or pale Chablis to wash it down, no newly-cut, well-buttered brown bread, did that solitary anonymous man inaugurate the first oyster banquet."

Another story makes the act of eating the first oyster a punishment. The poetaster also had his views on the subject:

"The man had sure a palate covered o'er
With brass, or steel, that on the rocky shore
First broke the oozy oyster's pearly coat,
And risked the living morsel down his throat."

And ever since men have gone on eating oysters. Emperors and poets, princes and priests, pontiffs and statesmen, orators and painters, have feasted on the favoured bivalve.

Man has made use of the oyster from the most remote antiquity. Among the débris of festivals which precede by ages the epoch of written history, oyster-shells are found. On the "midden heaps" of northern Europe they are often discovered, mingling with other rubbish and with stone implements, evidently the refuse of very ancient feasts. We have all read of the classic feasts of the Romans, which began with oysters brought from fabulous distances. Vitellius ate oysters all day long, and the idea prevailed that he could eat a thousand. Calisthenes, the philosopher, was a passionate oyster eater; so was Caligula; Seneca the wise could eat his hundred, and the great Cicero did not despise the savoury bivalve. Lucullus had sea-water brought to his villa from the shores of the Campania, in which he bred them in great abundance for the use of his guests. To another Roman, Sergius Orata, we owe the original idea of the oyster-park. He invented the oyster-pond, in which he bred oysters, not for his own table, but for profit.