OF THE NAKED OR SHELL-LESS MOLLUSCS.
The Sea-Lemon, Doris tuberculata, is one of the most attractive. It derives its popular name from its peculiar form, which is like that of half a Lemon cut longitudinally. It is generally of a yellow tone of colour also, which greatly adds to the fancied resemblance. It has its breathing apparatus exposed externally, like other Nudibranchs, spreading over the mantle, near the head, in a flower-like shape; and, as it moves slowly round and round the Aquarium, forms a very singular object.
The Doris pilosa is a pretty white species of the same order; and the little black shining Nudibranch, Runcina Hancoci, is a pretty and interesting creature. But the handsomest of the Nudibranch or naked-gilled tribe, as the term might be Englished, is the Eolis corronata, which forms certainly a splendid ornament to the Aquarium. Its general colour is a pellucid indistinct tone, of pinkish hue, the papillæ or branchiæ are in clusters, and the central canal is of a rich crimson. Different parts of the surface reflect the brightest metallic colours, and the whole creature has a very gem-like appearance. In captivity it is very active. Another species of Eolis has the power of making a singular clicking noise, like the Tritonia.
The Aplysiæ, or Sea-Hares, have been unenviably celebrated among their congeners as containing a virulent poison. The species common in the Mediterranean, A. Leporinæ, furnished the venom with which the infamous Locasta destroyed the enemies of Nero; and with which she eventually prepared, at the tyrant’s request, a draught for himself, but which he had not the courage to swallow. The British species, A. hybrida, might probably be kept in confinement.
Many of the Sea-Worms are very beautiful. The Nereis bilineata is very brilliant, with its crimson body brightly marked by two white longitudinal stripes.
The Phyllodoce are a class of Sea-Worms, somewhat resembling the land Centipede, which form curious objects of observation when they are in search of food. Instead of spreading a set of tentacles, like some of the Zoöphytes and Molluscs previously described, they have the faculty of turning the cavity which forms the stomach inside out, like a stocking, the inverted organ protruding from its mouth to a considerable distance, which, when it becomes sufficiently covered with the minute Infusoriæ which form its food, is drawn in, assuming gradually its natural position, where it remains till the nutriment so introduced has been absorbed, when the operation is repeated.
The Sea-Mouse, one of the largest and commonest of our marine worms, is of a flattened and somewhat oval form, pointed at each end, its general colour being pale brown. The clothing of silky hairs, however, with which it is invested, is so splendid, glittering in iridescent colours like the plumage of a humming-bird, that Lamark has appropriately named it Halithea, or Sea-Goddess—Linnæus having previously given it the name of Aphrodite, the Marine Venus. When, indeed, it receives the rays of light, and reflects them from the depths of the sea, rich with prismatic hues, the effect has been compared in splendour to that of the peacock’s tail when outspread in the sunshine. When in the Aquarium it crawls restlessly to and fro, as though anxious to exhibit its splendours in every possible point of view; the metallic tinges, changing with every position, being most magnificent by candle-light, when red and orange hues predominate, while by day-light pearly greens and blues are most frequent.
The bodies of many of the Euricidæ and Nereidæ exhibit changing colours of similar character, though less splendid; but many of them possess an opal-like tenderness and delicacy almost equally attractive.
The little Sea-Slug, Ægines punctiluceus, is a brilliant little creature, well worthy the trouble of being permanently established in our Aquaria. Its general colour is pale reddish-brown; but, with the aid of a moderate lens, it exhibits a number of small black tubercles, in the centre of each of which is a speck of resplendent blue or green, forming a succession of gem-like ornaments that have been compared, by enthusiastic naturalists, to sapphires and emeralds; but, without exaggeration, the jewelry of this little creature may be said to surpass that of the Diamond Beetle, notwithstanding his superior reputation.
A few Chitons—a sort of Sea Wood-Louse—would do well in a tank; and a specimen of Gastrophæna modolina is said to have thriven well during many months.
CHAPTER VIII.
THE FISH AND CRUSTACEANS OF THE AQUARIUM.
A marine Aquarium may be rendered very interesting without the introduction of fish, and as their presence requires that the water should be once each day aerated by means of additional water, introduced by the syringe or by a drip, continuing for some time from another vessel, many may prefer the lovely Sea-Weeds, curious Zoöphytes, and beautiful Molluscs, alone; as, if the balance between the amount of animal and vegetable life be felicitously balanced, and the natural scavengers, in the shape of Periwinkles and other Sea-Snails, for the consumption of decaying vegetable matter, and a few Prawns to perform a similar office for perishing Infusoriæ, or any other animal matter, be properly supplied—the tank may remain for a long time undisturbed, the supply of oxygen being ample for the lower classes of animal life alluded to. The beautiful Actiniæ, indeed, will exist in apparent health for a considerable time in water in which no vegetable growth has been introduced. Mr. Gosse describes instances in which the water in glass Aquaria, containing Sea-Anemonies, has remained perfectly pure for more than a year.
The addition of fish, however, undoubtedly enlivens the general aspect of an Aquarium very considerably; and many may not grudge the task of daily aerating the water, in order to enjoy the cheerful spectacle of their agreeable and ever-active movements. One or two young Flounders, very small, and the young of other species of flat fish, add much interest to an Aquarium, in consequence of their mode of swimming being so different to that of the class of fishes with whose movements the eye is more familiar.
Among the fish mentioned by the most experienced in the keeping of Sea Aquaria as best suited to that purpose, the first is the pretty little Tansy, Blennius pholis, with its bright scarlet eyes, and the many changing hues of its body. This little fellow will live and flourish in a tank with a poorer supply of oxygen than any other fish yet tried.
The fifteen-spined Stickleback, Gasterosteus spinachia, does well, and is very cheerful and brisk in his movements. Three or four would be an improvement to any tank.
Young of the gray Mullet, too, do well; for if the supply of oxygen be rather inadequate, they are observed to put their heads partly above the surface of the water, and obtain an artificial supply in that surreptitious manner. The black Goby, Gobius niger, has also been tried with success; but his voracious character—devouring without scruple even his own congeners—renders him on the whole not a very desirable tenant; and yet it is a fine sight to see the little warrior turn black when he seizes his prey, his turquois-coloured eyes dilating with fury.
Several other kinds are mentioned, in a previous page, in the list of animals placed by Mr. Gosse in his first experimental Aquarium.
The Pogge, Aspidophorus cataphractus, is a singularly formed fish that might be added by way of experiment. The plate-armour in which his body is clothed runs in regular longitudinal lines, showing eight sharp ridges, running from head to tail, that have a singular and unfish-like appearance. In confinement, however, he does not display himself to advantage, generally lying near the bottom of the Aquarium.
The beautiful crimson maculations of the Ancient Wrasse, Labrus maculatus, render him a very desirable tenant; but his size—small specimens being eight or nine inches long—causes him to be inconvenient; and, moreover, he is difficult to manage, and would probably require altogether a special treatment. One of the smaller Wrasses, however, Crenilabrus cornubicus, is a desirable guest; his minute size, and varying and often gay colours, rendering him very attractive. He is an active and eager searcher for food, but never takes any loosely floating object, only darting at and detaching such atoms as are attached to the different species of Algæ.
The Pipe-Fish, Syngnathus acus, is interesting in the tank, and also the two-spotted sucker, Lepidogaster bimaculatus, a prettily coloured and curious little fish, which has the faculty of attaching itself to the side of the tank, or any other hard flat surface, by means of two singularly-formed ventral fins, which act like the leather suckers by means of which boys enjoy the sport of lifting heavy stones at the end of a string. The spawn of this fish is like tiny amber beads, and is attached to shells and other substances.
Among the Crustacea fitted for an Aquarium, the common Prawn, Palæmon serratus, holds the first rank. In the first place, his cleansing properties, in devouring all decaying animal matter, are most important. But not less interesting are his graceful movements: Now, he steals stealthily over the pebbles or the fronds of the Algæ, with his long, slender, hair-like horns in gentle motion, with all the seeming wariness of a cat (the resemblance being increased by candle-light by the fiery glare of the eye); next, leaving his walking apparatus, or legs, inactive, he uses only the swimming members, which are larger and flatter, and bordered with a compact fringe; agitating these instruments with beautiful regularity, he rises in the water with graceful ease (see [Plate VI.]), his semi-transparent body, as he rises, giving to his appearance a strange and somewhat apparition-like aspect, which has caused him to be compared to a marine spectre.
The Prawn takes its food with its second feet, two-fingered hands or claws, and carries it to its mouth. The hands of the first pair of legs are only rudimental in appearance, but are precisely fitted to their special purpose. They are his cleansing apparatus; and it is most interesting to watch the operations of his toilet when he uses these fringes as brushes, with which he cleanses his whole person most thoroughly, being almost unmerciful in the amount of severe scrubbing to which he subjects himself.
An allied species, P. squilla, is scarcely distinguishable from P. serratus; but the handsome scarlet-striped Prawn, Pardulus annuticornis, about the size of a Shrimp, is quite distinct, and would make a valuable addition to the collection. The Lobster Prawn, also, Athanas nilescens, has likewise been tried.
Some kinds of Crabs may be admitted, but not many; for several are extremely voracious, and would soon clear off all the naked Zoöphytes and most of the Molluscs.
The Climbing Crab, Eurynome aspera, is interesting in a tank from his habits. His climbing is as graceful and skilful as that of a monkey, and when he has succeeded in perching himself upon the highest object in the tank, he forms a picturesque object.
Crabs, like Prawns, are sea-scavengers, and the kinds that do not attack living creatures as well as dead are consequently useful in a tank. The great Fiddler Crab, Portunus puber, is remarkably handsome. He is clothed, in part, with a velvety brown fur, and the bare places of his shell are of a shining black. His eyes are marked with scarlet, and there are a few touches of bright blue about the head. If introduced, his proceedings should be carefully watched.
There should certainly be a specimen of the Hermit Crab in a Whelk-shell; and the Cleanser Crab, Portunus depurator, has been tried, but these active and greedy Sea-Spiders must be closely looked after.
It remains to speak of the Star-Fish tribe, which affords some of the most beautiful and easily managed subjects for the Aquarium.
In the centre of the lower part of [Plate VI.] are a large and a small specimen of the beautiful scarlet species, Geniaster equestres; just above, to the right, the graceful pink Cribella oculata; further to the right, Asteria gibbosa; and immediately above the Cribella, the thin, leathery species, the bird’s foot Sea-Star, Palmipes membranaceus. All these species are small, easily managed, and especially suited to the Aquarium; as is also the finely-marked and long-rayed Ophicoma rosula, his deep scarlet, with bright black marks, and his slender limbs or rays, rendering him a conspicuous object. These Star-Fish glide round the Aquarium, by the aid of their thousand sucker-like feet, in a very interesting manner.
All the true Star-Fishes, the Asteriæ, have the body divided into rays, like a star, and are furnished with sucking feet, or cirrhi, which are tubular, and filled with water. The internal structure of these creatures is very intricate and beautiful, and the skeleton of almost any kind offers the appearance of that of some exquisitely symmetrical flower. There are fourteen British species of Star-Fish, the finest being the Sun-Star, Solaster papposa, the disk, surrounded with twelve or thirteen rays, varying in colour from scarlet to deep purple, the rays being sometimes of a different colour.
The Luidia fragilissima is also a large kind, sometimes two feet across, which is peculiar to the British shores. It possesses the peculiar faculty of breaking itself into fragments when enraged or captured; and, in a work by the lamented Professor Forbes, there is a very graphic and facetious account of a specimen that escaped him in a very determined way by a suicide of this kind.
Plate VI.
1. Edwardsia vestita.
2 & 3. Geniaster equestres.
4. Cribella oculata.
5. Asterina gibbosa.
6. Palmipes membranaceus.
7. Palæmon serratus.
Stars of this class, having the power to dislocate their structure, are popularly known as brittle Stars. Some affect to consider this faculty not so very wonderful; but let such suppose for a moment some higher animal—a man, for instance—gifted with a capacity for exploding his trunk and limbs into moderately-sized fragments—into joints, as a butcher would say—at any slight provocation, and then the character of such a power would appear very sufficiently extraordinary. It is possible that the fragments of the disruptured Star-Fish have the power, in each separate fragment, of renewing the absent portions, and that each portion thus becomes a perfect fish, the dissevered portions having been noticed to retain their vitality long after their separation. We know that the little Garden Lizard has the power of dislocating his tail without effort, and leaving it between the thumb and finger, when he is playfully caught by that appendage; and, also, that he has the power of renewing his caudal extremity within a very short period. It is thought, therefore, not impossible, reasoning by analogy, that the Star-Fish may possess powers of a similar kind, of a somewhat more extensive character.
The Amnion Star-Fish, called sometimes Five-fingered (Asterias rubens), belongs to the division Echinodermata, that is, skinned like the Hedgehog.
The Sea-Egg, Sea-Urchin, or Egg-Urchin, as it is sometimes called, belongs also to the Echinodermata, or Hedgehog-skinned class, and form interesting objects in the Aquarium; the flat species exhibiting much more evidently their close affinity to the Star-Fish tribe, than those of the more common spherical form.
To revert to other classes that occur to me as suitable objects for an Aquarium, I may mention the “Red-noses,” as they are graphically termed (Saxicava rugosa), a colony of which, peeping out of their holes in the rock, would form a very striking object; and if a piece of their native rock could be detached sufficiently deep not to disturb them in the recesses of their tube-like burrows, their removal “en bloque” would not be difficult. When touched, the Red-nose squirts a stream of water at you in defiance, and darts back into his cavern. He is a small bivalve, having his inner or immediate home within two rough brown shells. The double-tubed proboscis with which he is furnished is extended, when in search of food, to the mouth of his cave, in which position the appearance of its ruddy terminus has given to this tribe the characteristic name of “Red-noses.” How he contrives to bore a hole in the solid rock, with any of the soft pulpy members with which he is furnished, appears a mystery. Other Conchifers have, however, similar capabilities, their ingenuity not being confined to rocks, and their industry not being always harmless. Such, for instance, is that of the Teredo, or Ship-worm, a species of which has long proved so inimical to the formation of a Russian fleet in the Black Sea—the late war having, however, proved a far more serious impediment to the development of that portion of the Russian navy.
The Sea-Leaf, formed of twenty thousand or more cradles for young Polypes, is also a curious object. It is the Polyzoön, sometimes called the Hornwrack.
A few of the translucent Medusæ, in a young stage of their existence, might be procured and tried, though their transport would be difficult; and a group of creatures, of the genus Zoöthamnium, forming, as they do, an object like a little tree of glass, covered with trumpet-shaped bells, of the same crystalline aspect, each exhibiting its rotating circle of minute cilia in rapid motion within, would form a singular and beautiful complement to the wonders of the Aquarium, if its removal from its native depths, and its location in its new home, could be successfully managed.
CHAPTER IX.
CONCLUSION.
In conclusion, a few general remarks may be made, the observance of which will usually ensure success in the formation of an Aquarium. In the first place, if the vessel in which the Aquarium is to be established be home-made, care must be taken not to use any cement that has a disagreeable smell—which would be very soon fatal to creatures accustomed to the pure waters of the ocean. Scott’s cement is said to be better than putty, for fixing in the glass to the columns at the angles.
If cement be used to fix the rock-work of the miniature marine landscape, let it be the best Portland cement, which, when dry, must be soaked by filling the vessel with water, and the water changed several times before the tank will be fit for use.
The best sand for the artificial beach, or bottom, is the Thames’ sand, used by builders; but this must be washed several times, till the water runs off quite clear, before it is fit for use—any other kind of sand, if that cannot be procured, must be submitted to similar washings. Sea-water can be procured by furnishing the steward or captain of any Thames steamer, or the guard of a railway in connection with the coast, with a clean barrel; the charge, in either case, for carriage and trouble, would not exceed two or three shillings.
The artificial salt water has been found sufficient for Zoöphytes, but not for fish and other of the higher class of marine animals, except for a certain given time.
The composition for artificial sea-water is as follows:—
| Common salt | 3-1/2 | oz. |
| Epsom salts | 1/4 | oz. |
| Chloride of magnesium | 200 | grs. } troy. |
| Chloride of potassium | 40 | grs. } |
To these are added four quarts of water, and when the salts are thoroughly dissolved, say on the following day, the liquid must be filtered through a sponge; it is then fit for use.
Care must be taken to observe whether, when the sun shines and the light is bright, the silvery bubbles of oxygen form upon the fronds of the marine vegetation; and if not, it is certain that the marine plants are not in a healthy state, and must be renewed.
Mr. Gosse gives the following final directions as to the class of animals and plants that should be selected in preference for the experiments of beginners.
With regard to sea-weed, he observes, do not take Oar-weeds or Tangle; all the Fuci are of a slimy nature, which it is difficult to manage, and as their size is inconvenient, and they have but little beauty, their absence is not to be regretted.
Of animals, he says, take:—Of Fish—Blennies, Gobies, Wrasses. Of Mollusca—Aplysia, Periwinkle, Chitons, Scallops, and Burrowing Bivalves, such as Venus, Pullastra, &c. Of Crustacea—Eurynome, Portunus puber, Carcinus mænas, Ebalia, Corystes, the Paguri, Porcellana platycheles, and the Crangones, the Palæmones, that is, Shrimps and Prawns. Of Annelids—Pectenaria, the Sabellæ, and the Serpulæ. Of Zoöphytes—the Madrepores, and all the Actiniæ.
Few will establish an Aquarium without deriving great mental improvement, and the enlargement of their circle of acquirement, in a direction highly calculated to develop some of the best and highest feelings of our nature. Even the scientific cannot fail greatly to enlarge their sphere of knowledge in this new, and almost untrodden, field of research. The entomologist, sighing that there are no new Tiniæ to add to his already enormous list, no new Curculios with which to form another volume to the already portly series—these and other physiological Alexanders, weeping for new regions to subdue, may hail the Aquarium as a fertile source of further conquests; for, notwithstanding the numerous and curious discoveries of recent investigators, the depths of the ocean are as yet, comparatively speaking, one of the untrodden fields of science; and a glorious arena it presents—the Aquarium being one of the fairest channels for the detection of its myriads of yet hidden mysteries.
The marine Aquarium is, as yet, a plaything, a mere toy; but it is destined to become a far more important means of advancing science, and ministering to popular instruction, amusement, and wonder, than is yet dreamt of. It has yet to do for the ocean that which our menageries and vast gardens, devoted to the service of natural history, have done for the forests and mountains of the terrestrial portion of our planet.
We shall yet have tropical Aquaria, in which the temperature and qualities of the sea between the tropics will be so successfully imitated, that the glorious shells of those regions will be exhibited in living motion to our greedily-curious gaze; and fish gleaming with unusual dyes—metallic azure, and silvery crimson—will dart and glide in our tropic-tempered tanks, as in their own tropic ocean, for our delight and gratification. We are now entitled to expect from science, that it shall exhibit to us the wonders of the tropic deeps, as it has shown us the glorious plumage and velvet-spotted furs of the denizens of its terrestrial forests.
This is, in fact, the only thing that remains for us to do, in making a fitting popular display of the wonders of Nature, in order that we may surpass the doings of the ancients in that field of popular instruction and gratification.
Even in the days of Cyrus, we learn from the graphic Xenophon and other sources, that every eastern satrap had his “paradises,” in which the most curious animals of distant regions were preserved in a state of liberty, and in a manner suited to their natures, either for the sport of hunting or for the curious gratification of the eye.
The Romans, long before they had attained to the material wealth of the modern nations of Europe, had exhibited to the people of their capital all the noblest animals of Asia and Africa. Even the Giraffe and the Hippopotamus were familiar forms to the Roman populace; while, with the great modern nations of the west, the sight of these wonderful creatures is but quite a recent gratification. It only remained to the ancients to have exhibited a Titanic Aquarium, to render our triumph over their labours in the field of popular natural history impossible. Had but a Roman Warrington or Gosse developed the germ of such an idea, and an Osler existed to furnish the glass—the Pompey, or Cæsar, or Crassus, would not have been wanting to feast the eyes, both of patrician and plebeian Rome, with an Aquarium measuring hundreds of feet in length, in which the monsters of the deep would have been exhibited in deadly conflict, and human divers, armed with net and trident, like the retiariæ of their gladiatorial combats, would have encountered, beneath the waters, the Shark, the Whale, or the Torpedo, to the shouts of crowded circuses, the centre of which would have been a glass-walled ocean.
But a gigantic Aquarium is, fortunately, a feat that yet remains for modern science to achieve, and which it will doubtless accomplish. The day will arrive when we shall see the living Behemoth—the Titan of the deep—rolling majestic in waves of his native element, perhaps pursued by his cruel enemy the Sword-Fish, or harried by a shoal of Herrings, graphically exemplifying to a London crowd the origin of Yarmouth bloaters. Or we may see the dreaded Shark float round and round the vast glass prison seeking his prey, and the Shark-hunter of the south seas may be imported to exhibit his skill in a bloodless conflict—mocking the attempts of the sea monster to seize him, as the Spanish matador plays long with the infuriated bull; but without necessitating the same catastrophe to the animal, defenceless against the specially-trained skill of his human antagonist. We have already had our crystal palaces, covering their acres, and filled with objects of art and wealth from every quarter of the globe; it is not impossible, therefore, that we may have crystal-walled seas, in which aquatic menageries will form the last new object of fashion and wonder.
For the present, however, the Aquarium is, as I have said, but a toy, yet one full of pleasant instruction; and it doubtless contains the germs of a development, the precise direction of which it is at present difficult to guess.
THE END.
London: Thomas Harrild, Printer, Salisbury Square, and Silver Street.
Transcriber’s note:
Plate caption numbering discrepancies have been retained to match the Plate.
List of Plates, ‘pink’ changed to ‘Pink,’ “The Pink Ceramium 47”
Page 16, ‘georgeous’ changed to ‘gorgeous,’ “and the gorgeous colours”
Facing page 34 (Plate XII), full stop struck following ‘Plate,’ “Plate XII.”
Page 41, comma inserted after ‘βρυον,’ “Bryon (βρυον), a moss”
Facing page 48 (Plate III), full stop inserted after ‘multifida,’ “Nemaleon multifida.”
Page 59, ‘Zpoöhytology’ changed to ‘Zoöphytology,’ “known as Zoöphytology.”
Page 83, ‘aquainted’ changed to ‘acquainted,’ “all are acquainted with”
Page 89, second ‘the’ struck, “spines of the same”
Page 98, ‘his’ changed to ‘is,’ “he is difficult to”
Page 108, ‘Zoophytes’ changed to ‘Zoöphytes,’ “Of Zoöphytes—the Madrepores”