The Aquarium (Gosse)/Chapter 5
CHAPTER V.
"How various the shades of marine vegetation,
Thrown here the rough flints and sea-pebbles among!
The feathered Conferva of deepest carnation,
The dark purple Sloke, and the olive Sea-thong!
Every one who has paid a visit to Weymouth is familiar with the Nothe, an elevated promontory that juts out a considerable distance to the eastward, forming the southern boundary of the harbour. It is a favourite walk; and great numbers of persons climb on a summer's afternoon the steep steps that lead up to its grassy summit, whence they turn, and cast a glance at the busy shipyard and the narrow harbour lying beneath their feet, and, beyond the pier, at the crowded esplanade receding in its sweeping curve till it is lost in the distant shore. The long and lofty barrier of this headland affords a most valuable shelter from the violence of the south and west winds, completely protecting the harbour in this quarter; and the benefit thus gained is often sensibly appreciated when, from the quiet calm below, we mount the ridge, and suddenly encounter the force of a breeze that is curling the waters of the Bay, and covering the dark green space between us and Portland with broad sheets of driving foam. The extremity of the promontory is occupied by the premises of the Coast-Guard, whence those hardy fellows are often exercised in artillery practice, firing their one great gun at a signal fixed on a buoy some mile or two out at sea,
A fine and substantial jetty of hewn stone has been built out from the base of the point, lengthening the harbour; on the end of which a large lamp lighted with gas from the town indicates the entrance to the port in the hours of darkness. For the protection of this important work from heavy seas, which are apt to prevail from the south and east, and which have ere now proved very injurious to it, a sort of breakwater has been formed about thirty or forty yards off, which is called the Mixon. It was made by throwing large stones overboard, until a heap was accumulated, sufficient to appear above the surface. The action of the waves settled their angles one within another, and gradually gave the mass considerable solidity; and it now appears as a low island of rocks, covered at ordinary high tides.
Within the numberless crevices of this mass of unshapen stones, which run down to considerable depth, though without possessing that isolation of the contained water which would constitute them pools, grow Algæ of many species in more than littoral vigour. The margins of the heap, especially the shoreward margins, which enjoy a more protected sea, are fringed with luxuriant tufts, and the surfaces of the individual blocks are studded with hundreds of fine specimens. In fact it is a varied, well-filled, and fertile garden of marine botany, and the algologist who may visit Weymouth will find it well worth his while to explore the Mixon. It can be reached only by means of a boat, and can be examined only at low water of spring-tides, and then only (at least with any comfort) provided no sea is running, as otherwise the breakers wash over the mass, and prevent examination. A wet foot is pretty sure to be an accompaniment of the expedition, for the angular blocks, offering, here only projecting points, and there surfaces sloping in all angles of obliquity, and draped with wet and slippery beds of Enteromorphœ and other weeds, afford but a precarious foot-hold for one used to these rough rocks, and to an unpractised tread are sure to prove treacherous. In summer, however, a partial immersion in these crystal waters is an evil of no terrible magnitude.
The Laminariœ luxuriate on the shelving outer margin, and toss their broad brown fronds to and fro in the rolling seas, like forest trees that rock in the gales of autumn. But it is chiefly the red and green families of Algæ that flourish here; the Winged and the Sinuated Delesseriœ; the excessively ramified Plocamium, whose brilliant crimson trees are so much in demand by those who make mimic landscapes out of dried sea-weeds; the pencilled Polysiphoniœ; the brush-like Dasya; the feathery Ptilota; and various species of elegant Ceramia, so easily recognised by their regularly jointed stems and double incurved tips; and the tender Callithamnia, among the most delicately lovely, though the most minute of marine Algæ. Several species of Cladophora, also, here spring from the rocky surface in greater or less abundance, forming pencil-like tufts of various hues of green, some indeed dull and sombre, but others brilliantly vivid and silky. And, besides the large lettuce-like leaves of Ulva, which here attain unusual size, great patches of rock are covered with the equally large and still more tender fronds of Porphyra of a brownish-purple tint, bearing no small resemblance in texture and surface to gold-beater's skin, and which in the esteem of some persons, perhaps, presents the sole redeeming trait of "utility" amidst a Class proverbially "vile", since it contributes to the indulgence of their appetite. For this is the Sloke or Laver, which, being stewed to jelly and served up with lemon-juice, is a favourite dish at the tables of many. For myself, I am free to confess that the exquisite beauty of form and colour displayed by many of these humble plants; the delicacy of their simple structure; and the purposes which they evidently serve in the great chain of being, of which it has been truly said—
"From Nature's chain whatever link you strike,—
Tenth or ten thousandth,—breaks the chain alike;"
are sufficient qualifications to redeem them from the baseless charge of vileness, even without any pretensions to sapidity
And while I am speaking of beauty, I will mention a species of sea-weed that possesses it of a very peculiar character, and in an extraordinary degree. It grows in the vicinity of the Mixon, though not exactly on it; and indeed this is the only locality in which I have met with it. It is the Cystoseira ericoides. Between the Mixon and the end of the jetty, in about a fathom's depth, we discern, as the boat glides smoothly along, a bush here and there of large size springing from the bottom, conspicuous above the olive and purple bed of common weeds by its light greenish grey colour. These are the plants in question. It is difficult to procure a growing specimen, for the rocks to which the plants are attached are here all rather large and heavy masses, and the depth of water even at low-tide prevents the use of the hammer and chisel. By means of a boat-hook, however, I have torn up considerable portions of a shrub, from which I have then carefully severed uninjured branches, which, being bound to the surface of a shell or stone, survived some time in an Aquarium, and displayed their remarkable gorgeousness of colour to great advantage. None of this is visible when the specimen is removed from the water; it is a shrub with stout compact branches of a pale yellowish-olive hue, set with needle-like leaves, whence its trivial name of ericoides or "heath-like;" while another marked character is the swelling of the branches into oval air-bladders, which, though solitary in this species, more generally run in strings of several in succession, as indicated by the generic name Cystoseira or "bladder chain." But the moment the plant is submerged all its glory returns: the pale olive branches become invested with a most brilliant flush of iridescent light blue, not changeable in tint, though varying in intensity according to the play of light that falls upon it.
Thus it may be compared to some Christians, who are dull and profitless in prosperity, but whose graces shine out gloriously when they are plunged into the deep floods of affliction.
MY OWN TANK
As the principal subject of these pages is the Marine Aquarium, including, and indeed subsidiary to, the history of the plants and animals which it enables us to keep under our observation, it may not be impertinent in me to give some account in detail of my own. Hitherto I had contented myself with cylindrical glass vases, ten inches in height and five in diameter, which answer admirably for small objects; with wide shallow pans of yellow and white ware; and with a foot-bath of the latter. These, though affording opportunity for many interesting observations, were deficient in some points, which would be supplied by a Tank of ampler dimensions, with parallel sides to prevent unequal refraction and consequent distortion, and made wholly of plate-glass to allow distinct vision in every part.
Such a vessel I have had made under my own direction; and as it will be the chief medium of most of the notes that occur in the subsequent pages of this work, I will describe in detail its dimensions, form and structure; the mode in which I filled and stocked it; with some accounts of failure and disappointment to serve as beacons, as well as of success to stimulate with encouragement. I do not hold it up as a perfect example, but as an essay actually made, "with all its imperfections on its head."
The tank is 2 feet long, 112 foot wide, 112 foot deep; the sides and ends of 316ths plate-glass; the bottom of slate; the corners of birch-wood, turned into pillars, each surmounted by a knob, and united by a frame top going all round. The glass is set in grooves in the slate and wood, and fastened with white-lead putty. I first stocked it before the emanations of the putty &c. had sufficiently gone off; and hence the plants and animals died almost as fast as they were put in, rarely surviving the first night, although the water was renewed from the sea once and sometimes twice a day. The Mullet-fry and a few Actinias alone survived the experiment, which was continued for a week.
At the end of that time I emptied it, had it carefully cleansed and rinsed with fresh water, and allowed it to remain in the open sun and air for a week, when I judged all smell from the paint had ceased.
I now refilled it. The mode in which this was done was as follows. First I laid on the bottom a stratum of stiff blue clay, varying in thickness from two inches to half-an-inch. On this a layer of small pebbles, coarse gravel, fine gravel, and sand, was put, so as to afford varieties of bottom. Then pieces of rock were carefully put in, so selected and arranged as to make arched passages and overhanging shelters, with one mass rising pyramidally to within a few inches of the surface.
The sea-weeds, attached to fragments of stone, were now introduced; the larger and heavier on the bottom, the smaller and more delicate laid on the ledges of the rocks, or inserted into the crevices. Among the former were a large tuft of Furcellaria fastigiata, two of Chondrus crispus, two of Rhodymenia palmata, one of Dictyota dichotoma, a small plant of Fucus serratus, one of Laminaria digitata (young), two tufts of Padina pavonia, and several masses of Corallina oficinalis in the incrusting state. Among the latter were three tufts of Griffithsia setacea, one of Delesseria alata, two of Plocamium coccineum, and one large and one small bush of Phyllophora rubens. To these were added, about ten days afterwards, a mass of Zostera marina.
About 20 gallons of sea-water, dipped from the quay steps while the tide was coming in, were poured into the Tank, a plate being held under the stream, to prevent the displacement of the contents by the falling water. It was rather turbid at first, but soon cleared, and in about two days became quite crystalline, except a slight tinge of green, which always remained; not enough to alter the hue of any object in the vessel, but perceptible, by contrast with the clear air, when the whole body of the fluid was looked through.
No animals were put in till the third day; but from the weeds multitudes of minute creatures swarmed forth, quite peopling the water. At night the application of a candle revealed a vast number of tiny animals clinging to the sides, and visible through the clear glass; Annelides of the genus Syllis; Rissoæ and other minute shell-fish: but principally Isopodous and Entomostracous Crustacea, for the most part so small, as to require a lens for their detection. The careful examination of the water with the triple power of a pocket lens made manifest also that an immense number of Infusoria and some Rotifera were tenanting the Tank.
These, especially the Crustacea, could be drawn to any part of the vessel by the moving of the candle; for when this was placed within an inch or two of the side, the living atoms would presently be seen crowding up to that part by myriads, and studding the glass in the vicinity, just as if it were covered with fine dust. I subsequently availed myself of this acquaintance with the habits of the Entomostraca, to provide food for the smaller fishes; for I found that they soon disappeared, not a trace being left of their presence after the Tank had been stocked a few days, doubtless having been devoured by the Wrasses and Mullets. I therefore gathered some tufts of the more bushy sea-weeds, and allowed them to remain floating in the Tank for an hour or two in the evening, a candle being placed outside. The result was the same as I have described; the vast numbers that swarmed out were really astonishing; and I was pleased to see the little Mullets flock up to the spot where the light revealed the tiny prey, and pick the atoms from the glass, one by one, as fast as they could seize them; and yet the hosts crowded on, faster than they could be devoured.
The animals of which I could take distinct cognizance were as follows.
| 1 | Fifteen-spined Stickleback | Gasterosteus spinachia |
| 7 | Grey Mullet (young) | Mugil capito |
| 1 | Black Goby | Gobius niger |
| 1 | Corkwing | Crenilabrus Cornubicus |
| 1 | 5-beard Rockling | Motella 5-cirrata |
| 1 | Great Pipefish (young) | Syngnathus acus |
| 1 | Deep-nosed Pipe | Syngnathus„ typhle |
| 2 | Worm Pipe | Syngnathus„ lumbriciformis |
| 2 | Ashy Top | Trochus cinerarius |
| 1 | Navel Do. | Trochus„ umbilicatus |
| 3 | Common Periwinkle | Littorina littorea |
| 3 | Yellow Do. | Littorina„ littoralis |
| 1 | Purple | Purpura lapillus |
| 1 | Scrobicularia | |
| 1 | Anomia | |
| 2 | Common Cockle | Cardium edule |
| 2 | Ascidia | |
| 2 | Hermit Crab | Pagurus bernhardus |
| 1 | Hermit CrabDo. | Pagurus„ Prideauxii |
| 4 | Sand Shrimp | Crangon vulgaris |
| 1 | Prawn | Palæmon serratus |
| 3 | Crown worm | Serpula triquetra |
| 3 | White-lined Worm | Nereis bilineata |
| 2 | Thick-horned Anemone | Actinia crassicornis |
| 3 | Thick-hornedWeymouth Anemone Do. | Actinia„ clavata |
| 2 | Thick-hornedParasitic Anemone Do. | Actinia„ parasitica |
| 6 | Thick-hornedPlumose Anemone Do. | Actinia„ dianthus |
| 5 | Thick-hornedDaisy Anemone Do. | Actinia„ bellis |
The Actiniæ were dispersed about the pieces of rock, in the reticulate cavities of a large piece of Eschara foliacea, and in the holes of Coralline-covered stones. The Serpulæ and the Ascidiæ were attached to Oyster shells, as was the Anomia; the other animals, being vagrant, chose their own resting places and wanderings.
In about a week after the original stocking, the following animals were added to the collection in the Tank:—
| 1 | Æquoreal Pipefish | Syngnathus æquoreus |
| 1 | Rough Doris | Doris pilosa |
| 2 | Magus Top | Trochus magus |
| 1 | Nerit | Natica Alderi |
| 1 | Squin | Pecten opercularis |
| 1 | Pholas | Pholas parva |
| 1 | Pisa | Pisa tetraodon |
| 1 | Cleanser Crab | Portunus depurator |
| 1 | Ebalia | Ebalia Pennantii |
| 1 | Hermit (small) | Pagurus ? |
| 3 | Lobster-prawn | Athanas nitescens |
| 1 | Brittle-star | Ophiocoma rosula |
| 1 | Eyed Cribella | Cribella oculata |
| 2 | Scarlet Sunstar | Solaster papposa |
| 1 | Birdsfoot Star | Palmipes membranaceus |
| 3 | Gibbous Starlet | Asterina gibbosa |
| 1 | Purple-tipped Urchin | Echinus miliaris |
| 7 | Scarlet Madrepore (from Ilfracombe) |
Balanophyllia regia |
| 3 | Cloak Anemone | Adamsia palliata |
Thus there were nearly a hundred animals in this Tank; a number which I found far too great; for though they did not crowd the vessel at all apparently, nor seem disproportioned to the space they occupied, it became evident that the exhaustion of the oxygen of the water went on more rapidly than it could be renewed, either by the evolution from the living plants, or by the combination with this of artificial aeration, by allowing two or three gallons a day to drip from a vessel suspended over the Tank at the height of about four feet.
For about ten days the animals appeared pretty well; a little diminution occuring from the assaults of the predatory species on their weaker fellows. Then many of the more delicate began to grow sluggish and manifestly unhealthy; some of the fishes, some of the mollusks, particularly the univalves, and the smaller Crustacea, died off one by one; and the water began to have a tainted odour, arising, as I discovered, from the carcases of some of the animals that had died beneath the shelter of the stones.
The whole contents were therefore removed: the plants and animals, such of them, at least, as appeared in health, being temporarily placed in a pan, while the water, sand, gravel, and clay were thrown away, the interior of the Tank well cleansed, and refilled with new materials. With these I got on better; though, as it was always an object with me to have as many animals under observation as possible, I did not care to confine the number to such as would maintain the balance with the plants. I preferred to change the water periodically, as the sea flowed invitingly up to the very door, and accordingly renewed it regularly about once in three weeks. Hence this must not be considered as evidence pro or con on the philosophy of the subject, a question which Mr. Warington's experience triumphantly settles.
THE BLACK GOBY
This fish (Gobius niger), of which I had several about 3 inches long, soon became tame, feeding readily After a few weeks they would come out of their shelter as soon as a stick was put into the water, and at length grew so bold as to snap at and seize the stick. A little Two-spot Goby (G. Ruthensparri), elicited the cannibal propensities of his black cousin, for no sooner was the little creature put into the tank, than presently the Black Goby caught sight of him, and rushing towards him seized him by the tail, which was in a moment engulphed in the capacious throat. The Blackie glared like a demon as with dilated head he held fast his victim, clutching further and further hold by repeated jerks: the delicate, pellucid head of the unfortunate prey, projecting from the cavernous mouth, panted and rolled its eyes in pain, but there was no escape; for now nothing was visible but the head, when the ferocious victor shot under an umbrageous weed, and on my next sight of him all trace of his meal was gone.
The ferocity of this little fish is manifested even towards its own species; one can scarcely come within sight of another without the stronger darting at the weaker, and pursuing him with pertinacity for a considerable distance, following him in all his doublings and shifts, and through all the crevices and passages which he essays in flight, for some time.
The Black Goby habitually loves retirement; lurking under the shelter of the rocks and weeds, yet often coming into view. He proceeds by starts, as if with effort, shooting a few inches, and resting a while between the strokes, never floating and turning about in the water, like surface-fishes. Near the bottom is his proper sphere; he never comes near the surface except when, very hungry and eager, he sees a fragment of food at the top, and shoots up perpendicularly to seize it, turning instantly downward to his depths again.
The colours of this fish are subject to great change, probably connected with the passions. When it seizes its food, especially if it is a living prey, the general hue is a dull bluish black, nearly uniform, but occasionally varied with slight cloudings of a deeper tint of the same colour. At other times, when lying still, the body is of a pale pellucid brown, with drab clouds, and patches of white specks. The first dorsal is always of an orange-fawn colour. The eyes are striking, being of a pale blue, exactly like two turquoises.
It is a characteristic of the fishes of this genus that the ventral fins are soldered together, as it were, by their inner edges, so as to form an oval disk. The object of this is the adhesion of the body by means of a vacuum. Col. Montagn, indeed, says of this species,—"In no instance have we observed that they adhered either to rocks or to the bottom of the glass vessel in which they have been kept alive for several days."[1] But I have seen the Black Goby adhering to the glass sides of my Aquarium by its ventral sucker repeatedly, though not until it had become familiarized to its home by several weeks' captivity.
THE GREY MULLET.
Some half-dozen Mullet-fry, from an inch to 114 inch long, proved very hardy, surviving apparently uninjured, even when the exudations from the putty and paint killed everything else, even the Actiniæ, before the Tank was seasoned. I attribute this immunity to their constant habit of keeping at the surface, where the water becomes perpetually aerated; for they rarely descend far below this, but play day and night at the top of the water. They are social little fishes, congregating together into a little schull as soon as put in, and always manifesting a tendency to association. They were amusing, from their liveliness, being never at rest, but ever swimming waywardly to and fro, most vivaciously; and from the eagerness with which they fed. Any minute atoms of food, either vegetable or animal, they greedily devoured. A bit of apple or pear-pulp, or of a ripe plum, or crumb of bread, slightly chewed and spat into the water, became the centre of rapid evolutions, the result of which was that every atom was cleared away before it had descended many inches below the surface. A morsel of meat, or of fish, cooked, or the flesh of prawn, treated in the same way, was devoured with the same eagerness; but perhaps the favourite food was the spawn of a Prawn, or Shrimp, either cooked or raw, every egg of which was snapped up as it sank.
They were rather pugnacious, chasing each other about, when one was more successful than usual, just as chickens do, and often snatching the food from each other's mouth.
When, through a predominance of animal life over the vegetable, or from any other cause, the water in the Tank has become to a considerable extent deprived of its oxygen, I have noticed that the little Mullets endeavour to supply the deficiency by protruding their mouths from the surface and sucking in mouthfuls of air, presently disgorging a number of minute bubbles, generally from the mouth, but occasionally through the gill-aperture. That animals of aquatic respiration are able for a time to oxygenate their venous blood from air alone is proved by the fact that many Fishes, Mollusks and Zoophytes, are able to survive for a long time a privation of water, provided their respiratory organs be exposed to the atmosphere, and be preserved from becoming dry; while immersion in water from which the oxygen has been exhausted would presently prove fatal.
These little fishes afford another example of the power of mental emotions in changing colours. When pursued and caught with a net, in order to transfer them from one vessel to another, they become of a pale semi-pellucid drab hue, on the back, with three reddish lines. But after they have been put in, they gradually resume their original colour, appearing in a few minutes of a dark iron grey. Doubtless fear produces this change, as it does in some of the Reptiles, the Gecko for example, as I know from observation.
THE ANCIENT WRASSE
Among the fishes which are now brought to market, the Wrasses are conspicuous for the splendour of their colouring. They have put on their summer attire;—I know not whether, like our humble country belles, they choose Whitsunday as the day of their first appearance in holiday hues, but it was just about that time that the magnificent Ancient Wrasse (Labrus maculatus) first fell under my notice, and since that time the species has become increasingly common.
The fishermen call this, as well as other species of the same genus, by the name of Conner. They take it chiefly with hook and line on rocky ground, and as the hook often catches the fish by its thick fleshy lips, no material injury is suffered by it. Hence I get specimens of remarkable beauty brought to me alive and in health, notwithstanding the small dimensions of the vessel in which they are held, perhaps a slop-basin, or some three or four in a little mess-kid, barely wide enough to allow them to turn. But this genus is very hardy, and one of the most easily kept in an Aquarium; a fortunate circumstance, seeing that the splendour of several of our species is such as can scarcely be exceeded by the most richly-tinted denizens of the tropical seas.
Great variety in the hues, and in their arrangement or pattern, is displayed by the Ancient Wrasse. Two specimens can scarcely be found exactly alike. Red and green are the ordinary hues, sometimes pretty equally balanced, at others the one hue predominating almost to the exclusion of the other. The colours too run through various gradations; the red from orange to scarlet, blood-red, and crimson; the green from blue to sea-green, grass-green, olive and brown. One of the most beautiful varieties that I have seen, and one not uncommon, is that in which the green is almost obliterated, appearing only on the head and shoulders; while the body, brown above, softening to silver-white on the sides and belly, is covered by a net-work pattern of deep vermilion, the meshes being irregular, but massive, and most rich in effect. The fins are often orange, with bands or spots of transparent green.
The Frontispiece to this volume represents such a specimen, a little less than the natural size. The fish attains, indeed, much greater dimensions, but the most brilliantly coloured individuals are usually about six inches in length. I have represented it as lurking under a projecting ledge of rock, a situation it loves to haunt, under the shadow of the branching tufts of sea-weeds, from which it picks its insect food. The Sea-weeds introduced into the picture are as follows:—immediately in front of the fish is a plant of Chondrus crispus; below its breast is the woolly green Cladophora uncialis, a little species remarkable for its compactness, and for the abrupt termination of its tufts. Towards the left are seen two or three fronds of the curious and elegant Peacock's Tail (Padina pavonia), of which I have something to say presently; while springing from the same point, and arching over the back of the fish is a single leaf,—almost as thin and pellucid as tissue-paper,—of Punctaria latifolia.
THE CORKWING
The most common of all our Wrasses is the little Corkwing, (Crenilabrus Cornubicus). It is less pretentious than some of its fellows; yet bright-coloured specimens are very pretty, and their minuteness, hardiness, and lively manners make them very desirable tenants of an Aquarium. The common dimensions are about two inches in length, but specimens are not rare of twice that size. The colour is green, more or less brilliant; large and well-coloured individuals may be confounded with the Green Wrasse (Labrus Donovani), which is also not rare with us; but the little Corkwing may be distinguished by having the fore gill-plate minutely toothed along its free edge, and by a black spot on each side of the tail, just before the commencement of the tail-fin. Mr. Yarrell speaks of the Green Wrasse as if it were a great rarity; but I have had many specimens, some of which agreed accurately with Donovan's beautiful figure. It attains six or seven inches in length. To both species Ovid's descriptive line will apply:—
"Tum viridis squamis, parvo Saxatilis ore:"
for all the Wrasses have the mouth small, though the lips are thick; and all may be designated by the term Saxatilis, or Rock-fish.
The little Corkwing frequents the fissures in the rocky ledges, and is abundant all along the quays within the harbour, hiding beneath the hanging fringe of Fuci, that grows between tide marks. The prawn-catchers take them abundantly with their dipnets, when raking these sea-weeds; in company with the Fifteen-spined Stickle-back (Gasterosteus spinachia), and other small harbour-fishes.
A little Corkwing about two inches long, more than usually pretty, being of a bright green hue, with the caudal spot distinct and black, was a tenant of the Tank from the first. He was a fish of business never for a moment did he swim about as if at leisure, but incessantly pursued one occupation, that of searching the sea-weeds for minute animals. It was pleasant to see with what diligence and sobriety, for he was never eager or in a hurry, he pried into all the recesses of the leafy weeds, especially the bushy Chondrus, taking all positions and attitudes in order to scrutinize the inmost corners; and with encouraging success, for he was continually picking off something, invisble indeed to my eye, but eaten with evident gusto, to judge by the smacking of his lips. I suppose these were chiefly Entomostraca, or perhaps Infusoria, which the globular crystalline lens of his eye magnified at the short distance at which he saw them. This distance, which was commonly about half-an-inch, was made sufficiently manifest, by the action of the fish, for the snap was made doubtless the moment the prey was seen. I never once saw the Corkwing attempt to take or even notice any floating atoms of food, but only such as was attached, either to the Algæ or to stones.
This pretty little fish came to an untimely end in a singular way. A large specimen of the Parasitic Actinia was in the Tank, a species which shoots out its thread-bearing filaments in unusual abundance and to great length, when alarmed. I suppose the Corkwing must have accidentally touched the Zoophyte in passing, but this I did not see. On looking at the Aquarium, I saw the little fish with one of the filaments sticking to its mouth, evidently the accident of that very instant. It was greatly distressed; darted hither and thither wildly as if in agony; soon lay down on its side, and though two or three times it started up and essayed to swim, it was presently dead.
PIPEFISHES
The Pipefishes are rather uninteresting tenants of an Aquarium; their fins are small and of little power, hence their motions are ordinarily slow. They hang about in all attitudes, of which the perpendicular, either with the head upward or downward,—is a favourite one. I have a very young specimen of the Great Pipe (Syngnathus acus), a half grown Deep-nose (S. typhle), and a rather large Æquoreal (S. æquoreus), about 15 inches long. This last is slow and unwieldy, possessing no fin but the dorsal, while the former two have tiny pectorals which are fluttered with a rapid vibration, and a small fan-like caudal. All the species flutter the delicate and filmy dorsal fin, at intervals, though but little effect can be produced by such an organ in locomotion.
THE TWO-SPOTTED SUCKER
The dredge frequently brings up specimens of a pretty little fish adhering to the interior of old bivalve shells, or to stones. It is the Two-spotted Sucker (Lepidogaster bimaculatus), which owes its generic name to the circumstance of the ventral fins being united into a concave disk; by the application of which to any smooth surface, and the muscular withdrawal of the central parts, producing a vacuum, the animal adheres with considerable force; exactly on the principle of those suckers that children make of a piece of wetted leather at the end of a string. The little fish is not more than two inches long, somewhat tadpole-shaped, but prettily coloured of a pale crimson or carnation, with an oval eye-like spot on each side, of a deep red hue.
When put into a vessel of water (no easy matter without injuring it, as it adheres so firmly to its hold), it immediately clings to the side of its new habitation, or to the first solid substance with which it comes into contact. Here it will probably remain for a considerable time, unmoved, or now and then shift its position a few inches, or take a wayward start, and wriggle along with an awkward sort of agility to some other part of the Aquarium, to which it sticks fast in a moment as before. During the night it is much more restless; but, so far as I am aware, it has no power of hovering in the water, or swimming deliberately to and fro as other fishes do, its locomotive powers consisting only of the ability to shift from one stationary position to another.
As it thus has no power of pursuing prey, I conjecture that its subsistence is derived from those microscopic organisms which are scattered abundantly through the water, and which furnish support to multitudes of other creatures more strictly immoveable. In the case of these, which are for the most part invertebrate, strongly ciliated surfaces are provided, which produce constant and forcible currents, and thus the floating atoms in the surrounding fluid are carried along to the orifice of the digestive canal. Our little Sucking-fish has no external apparatus of cilia, that I am cognizant of, but a similar effect is produced in another way. I have noticed that while this little fish remains stationary, being fast moored by its breast anchor, it maintains a constant and regular fanning with its filmy pectoral fins. This habit seemed to me at first useless and unaccountable, but on consideration I have little doubt that its purpose is to produce a more free and rapid change of the surrounding water; and that it is one of those compensatory actions that we frequently meet with in physiology, and that are so interesting.
In the tropical seas I have had many occasions of witnessing the actions of a still more singular Sucking-fish, the Echeneïs. The notion put forth in books, that this fish, being a very slow swimmer, needs to be carried along by others, is simply absurb, and must have been formed by those who never saw the fish alive. It is in no wise inferior, in swiftness or power, to fishes of the same size with which it associates, the Sharks for instance to which it so commonly affixes itself. The Echeneïs bears a very close resemblance, when seen in the water, to a young Shark. It is fond of attaching itself to a grown Shark, usually choosing a spot just behind the pectoral fin, but it as commonly adheres to the rudder or to the bottom of a ship. I have thought that the singular habit may be connected with its manner of taking food; especially as the mouth, owing to the projection of the lower jaw, opens on the upper side of the muzzle. Now when the coronal disk is affixed to any foreign body, the lips are made to touch the latter also. We know that there are multitudes of minute animals, such as Crustacea, Cirripedia, &c. that live parasitically on the bodies of marine animals, and on foreign objects habitually submerged. If the Echeneïs feeds on these, there is an obvious reason why the head should be affixed to the surface during the dislodgement of the adhering prey, in order to acquire greater steadiness, as well as a leverage by which to act more effectively. What confirms this view, is, that though the fish may continue to be seen, say on the ship's rudder, for hours, it is not continually adhering; but ever and anon shifts its position, detaching itself for a moment, and then adhering again instantly.
Several times lately I have had brought up in the dredge, old valves of the Cockle, Scallop and Oyster, the concave surfaces of which were partly covered with considerable patches of what looked like amber-coloured beads,—such as are used to make bead-purses,—set as close as they could lie, but only in a single layer. They adhere quite firmly to the shell; and I knew that they were the spawn of some fish or crustacean, but was at a loss to know what. On one occasion, in the middle of the summer, I found the little fry escaping, so that the glass vase into which I had dropped the valve, was presently quite peopled with tiny fry; their gelatinous hyaline bodies barely visible, and their presence only indicated by the pair of lustrous, green goggle-eyes, which with the intervening head constituted by far the greatest portion of each little creature
From that charming work "Excursions to Arran," by the Rev. D. Landsborough, D.D., I learn that this spawn was laid by the little Two-spotted Sucker.
DOUBLE VISION
There is a phenomenon which has long been noticed in that singular reptile the Chameleon, and long supposed to be quite anomalous. It is that the eyes, which in most vertebrate animals move only in unison with each other, and as if by a common impulse, are here quite independent; the one glancing hither and thither while its fellow remains motionless, or looks in different directions.
A few years ago Mr. Lukis of Guernsey observed that the same peculiarity existed in the Sea-horse (Hippocampus) a curious little fish of the Syngnathidœ or Pipefish family. In my "Devonshire Coast" I mentioned the Worm Pipefish (Syngnathus lumbriciformis) as a second example of the phenomenon in this class of animals; but I have since found that it is by no means so rare as it had been supposed. All the Pipefishes display it; the Suckers (Lepidogaster), tiny fishes of low organization, manifest it strongly: in the Little Weaver (Trachinus vipera) I have remarked it very distinctly, and with more than common admiration, on account of the unusual beauty of the eyes in this species, which resemble turquoises set in gold.
The Wrasses (Labridœ) have the power of separate motion, but in a less degree: in the Butterfly Blenny (Blennius ocellaris) and the Gattoruginous Blenny (B. gattorugine) it is more or less distinct, in the former more than the latter. The fishes just mentioned (the Blennies and the Wrasses) have the faculty of moving the two eyes in unison as well as independently, apparently at pleasure.
These are all the species in which I have noticed the phenomenon of separate eye-movement, but I suspect it will be found to prevail extensively among fishes. It is a subject worthy of investigation by the comparative anatomist. The effect to the beholder, if he is in a position to see both the eyes of the animal at a glance, is highly singular and interesting
THE HONEYCOMB CORAL
A person who has never seen it before cannot but be struck with the appearance of a large leafy Coral (Eschara foliacea), which grows in the form of broad but thin plates, twisted and involved in irregular folds, and sending off other plates at right angles, so as to constitute a sort of honeycombed structure, rising to the height of five or six inches, and covering a space even much greater than its height. Its colour when recent is a fine light red or brownish orange, and its aspect is so noble that one is tempted to think it rather a production of the tropical seas than a native of our northern clime. It is always a welcome guest, not only for its intrinsic merits,—yet it is a charming object in the Aquarium,—but also because of the variety of animals which make their abode in its ample winding chambers. The Prickly Scallop (Pecten varius) is frequently found in it; it is usually crowded with the little Masked Broad-claw (Porcellana longicornis), which plays at bo-peep in the galleries; the deep-water variety of Actinia clavata, and A. bellis, occasionally occupy a chamber, and divers kinds of Nereidous worms crawl freely through it. A beautiful specimen is now in my Tank, which has grown like a noble crown around the summit of a conical stone, the whole being nine or ten inches in height. The basal stone is densely covered with parasitic Zoophytes, and tubicolous Annelides of many species.
But our admiration of this handsome Coral is much heightened when we know something of its nature. We see that its walls, which are not more than one thirtieth of an inch in thickness, are composed of stony substance, yet very brittle. Closer examination shows that this thickness, small as it is, includes two ranges of cells, which are placed back to back, opening by oval orifices on both sides of the walls.
Every cell is inhabited (or rather has been, for the older ones are dead and vacant before the younger are formed) by an active Polype of the Bryozoan Class, whose head, crowned with a funnel of radiating ciliated tentacles, protrudes from the orifice or is withdrawn into it at pleasure. These all are united by a common life; a common bond of sensation and of nutrition connects the whole of the individuals into one compound being. A single Polype, inhabiting a solitary cell, began the colony, which has grown by the continual formation of new individuals on every side, as buds grow into branches, which bud again and form a tree.
Some idea of the populousness of such a community may be gathered from the following calculations. I took a piece from my specimen, on which I carefully marked out an area of one eighth of an inch square. Within this I found the orifices of 45 cells; as the rows are double, this would give 90 cells in every square eighth of an inch; or 5760 cells in a square inch. Now, in a moderate-sized specimen of the Eschara, such as several that I have had in my possession, there are at least 100 square inches of wall, including all the convolutions, and all the partitions, which would give a population of 576,000 inhabitants; so that a well-grown mass of this coral may bear rank, for multitude, with Vienna, Paris, or perhaps London itself.
Montgomery's exquisite description of the labours of the Coral-worms are scarcely less applicable to the architects of our humble Eschara than to those which rear the colossal reefs and isles of the Pacific. Familiar as the lines are, I must quote them.
"Millions on millions thus, from age to age,
With simplest skill, and toil unwearyable,
No moment and no movement unimproved,
Laid line on line, on terrace terrace spread,
To swell the heightening, brightening, gradual mound,
By marvellous structure climbing tow'rds the day.
Each wrought alone, yet all together wrought,
Unconscious, not unworthy instruments,
By which a hand invisible was rearing
A new creation in the secret deep.
I saw the living pile ascend,
The mausoleum of its architects,
Still dying upwards as their labours clos'd:
Slime the material, but the slime was turn'd
To adamant, by their petrific touch:
Frail were their frames, ephemeral their lives,
Their masonry imperishable. All
Life's needful functions, food, exertion, rest,
By nice economy of Providence,
Were overruled to carry on the process,
Which out of water brought forth solid rock."
Pelican Island.
It is true that, as yet, we get but occasional glimpses of these revelations: it is only now and then that a homely object becomes a picture of something higher, a dissolving view, that, while we gaze, changes its lineaments into something of higher beauty and deeper interest, a transparency lighted up in every feature by a glory behind it. "Now we see through a glass, darkly." But hereafter much may be plain and patent, that now we only guess at; and the curtain may be broadly lifted that now hangs thick and close over Creation, permitting but occasional rays to struggle beneath its fringes.
Little, indeed, my dull eyes can see of heavenly teachings in earthly things; but there is one resemblance to a high and holy mystery that I have delighted to trace in one of the lowliest forms of sentient being.
There is a City hidden in heaven, but destined, by and by to come down to earth; it rises street above street, and wall above wall, and battlement above battlement; its streets are of gold transparent as glass, its gates are of pearl, and its foundations and walls of crystal are garnished with precious stones. It is peopled by happy spirits in resurrection bodies, by star-crowned men who have washed their robes and made them white in the Blood of the Lamb,—by none else. Nay, the City is composed of these, it is made of living stones, built up one by one in slow and gradual progress, each with an individual consciousness, an individual life.
But (here is the mystery) the City is an individual being, it is a Bride, a Wife. It is the Church of the living God, the Bride of Christ, the Lamb's Wife. One life runs through the whole body, the life of Christ, communicated in resurrection power and perpetuity to her. He bought her,—a pearl of great price,—with all that He had; He nourishes and cherishes her, and He will soon raise her to share his throne.
Is it fanciful to discern a faint shadow of these glories in a poor Polype. If it is, bear with the fancy, for it is not lost time to turn our thoughts heavenward for a moment, whatever be the occasion. When I look on the multitudes of Polypes inhabiting such a structure as I have alluded to, each bearing his starry crown, and all engaged in harmony, building up, wall by wall and cell by cell, an edifice whose walls are of crystalline clearness, often studded with what look like gems,[2] and whose cells are closed with pearly doors;[3] when I watch the building growing up into a City, a commonwealth, of myriad individuals; when I know that, besides the separate life of each, there is a common life, a bond of identity, that constitutes the vast assemblage but one Being,—One though Many—I cannot help thinking of the heavenly City, the Jerusalem which is above.