Philip Henry Gosse

If we could roam at pleasure over the bottom of the sea, with the privilege of using all our senses as effectually and as comfortably as in the air, we should doubtless see some wonderful things. We might not, indeed, find all the useful and ornamental articles that drowning Clarence saw in his dream, but doubtless we might substitute for them things that he never dreamed of, things that the eye of man was not as yet cultivated to see. What opportunities for enlarging the bounds of science are possessed by the engineers that have been working many hours a day, for years past, at the great Breakwater in that prolific field of marine life, Weymouth Bay!—working in a capacious diving-bell at the bottom of the sea. But there are many reasons why we can expect nothing in the way of natural history from them. Perhaps not one of them has ever been taught to think upon any of the strange forms that might occur, which do not commonly minister to the pocket of man in the market, as anything but mere rubbish not worth a second glance, or something hurtful or nasty to be crushed beneath the heel. Or if, perchance, an observer of nature’s beauties be engaged in such an occupation, his time would be so fully taken up with his urgent duties, as to preclude attention to such amenities. Besides which, the loads of enormous blocks of stone already shot down on the sea-floor, which he is there to arrange and settle, must pretty well have smashed and covered everything which had revelled in dull enjoyment there, before his arrival. Still I fancy I should like to borrow his diving-bell on a holiday, and roam a little beyond those wildernesses of broken stone, picking up treasures here and there such as the scraper of the dredge has never yet been able to gather out of the crevices and crannies of those deep-water rocks.

But such a desire is at present hopeless; and we must be satisfied with such resources as are at our command, thankful that the dredge, and the trawl, and the keer-drag, the fisherman’s deep-sea line, the lobster-pot, and the sounding-lead—are all contributing to our acquaintance with the curious, the uncouth, the wondrous, the beautiful, that lurk far down in profundis.

Let us then go back to the results of our dredging day that we so much enjoyed a few weeks ago. A portion of its produce yet remains in buckets and pans, waiting for a further overhauling; and it will doubtless yield us some objects worthy of an hour or two’s investigation.

LOBSTER-HORN CORALLINE.

The first thing that our fingers pull up is a great tangled group of Sertularian Hydrozoa, of which the finest part consists of some half-dozen stems of Antennularia, called, from obvious resemblance, the Lobster-horn Coralline.[133] These are nearly straight, somewhat stiff, unbranched stems, a foot or more in length, with an uniform thickness of about a line, of a buff-yellow hue, closely divided into short joints. Each of the joints gives origin to a whorl of very delicate bristles, giving a hairy appearance to the whole affair, but which under magnifying power are discerned to be colourless, jointed filaments, bearing on the inner shoulder of each joint a tiny glassy cup (hydrotheca), within which resides a minute many-tentacled polype. The stems spring in close groups from an obscure root-mass of tangled threads, which cling to stones and shells, and afford a mooring to the Lobster-horn, which in its turn affords support to miniature forests of other Hydrozoa, slenderer than the finest hair—Laomedea, Campanularia, etc., which crowd together on it, especially around the bottom, and make the investigation of any one specimen very difficult. These have their polype-cups of exquisitely elegant forms, and I see on the latter many of the urn-shaped vessels (now called gonotheca), out of which issue what appear to be distinct and independent forms of life, as unlike the parent as can well be imagined, but exactly like the little naked-eyed MedusÆ that we lately looked at. This, however, is not properly an animal at all, but only an organ (the gonophore) which has the faculty of maintaining a separate existence, and which is destined to give birth to ciliated embryos, like the planula of the Aurelia, that attach themselves, and develop into new CampanulariÆ. Most wonderful are the processes and phases of life which have been discovered in these zoophytic forms.[134] A volume might be written on them, full of praise to the all-wise God.

PLATE 31.
P. H. GOSSE, del. LEIGHTON, BROS.
PYRGOMA ON A CORAL. SCALPELLUM. LOBSTER-HORN. NECKED BARNACLE.
COMMON BARNACLE. PORCATE BARNACLE.

Now, however, we must turn aside to look at other objects. Attached to the base of the Lobster-horn, we find several examples of an interesting Cirripede.[135] It is of a dirty buff, or drab hue, semi-transparent, in outline something like a butcher’s cleaver, handle and blade, or still more like a silver butter-knife, but much thicker in proportion; the handle represented by the cartilaginous and flexible stalk, the blade by the compressed valves. These vary much in regularity of form, some being nearly oval, little wider than the stalk, others angular and much wider. The body throws itself vigorously about on the stalk, when disturbed. The valves open, and out comes a widely radiating hand, of brilliantly glassy fingers, the joints and comb-like bristles of which glitter and sparkle as I hold it up in a tumbler of sea-water, examining it with a lens, with a lamp behind. It remains some seconds expanded, as if enjoying contact with the water; or perhaps, if I may draw inferences from some slight twitchings, feeling and testing for the accidental presence of invisible atoms that might serve it for food; then suddenly the fingers close together, and the hand is drawn in with a snap, as if it had taken some prize, though the lens had revealed nothing there. Soon it opens again, and exhibits the same manoeuvres. A front view of the hand, the bristle-like fingers radiating in all directions, is a very attractive object for a low magnifying power. There are several tiny ones in another group, the bodies of which are not bigger than hempseed; these make their grasps apparently at random, with regular alternation, much as the commoner Barnacles do.

Of these latter we have no lack, many of the rough shells and small pebbles being incrusted with crowded colonies of the commonest Acorn Barnacle.[136] We see the same species, by tens of thousands, covering roods and roods of the seaward surfaces of our rough rocks between tide-marks. They rarely exceed one-third of an inch in diameter at base; but there is a much more massive kind, rough with ridges and furrows, and hence called porcate, occasionally found adhering to the jutting angles of rocks hereabout, and much more commonly on the coast of South Wales, around Tenby.

These Acorn Barnacles have no foot-stalk, but adhere by the whole broad base to the rock or shell, on which a floor either of strong stone, or of thin membrane is formed, and from whose margin the stony plates arise, enclosing a more or less conical chamber, with an orifice at the summit. If we look in at this during the life of the animal, we discern, a little below the rim, some angular valves, which meet with a straight suture, and close the interior. These are moveable, however; and under water they open like folding-doors, and a hand of many fingers, each composed of many joints, modelled on the same plan as that of the Scalpellum, but less delicate, protrudes, which makes its cast for prey, and is withdrawn beneath the again-closed valves.

The winds and waves not unfrequently bear into our harbours fragments of spars, old water-casks, or planks, from the hull of some ill-fated ship foundered in the inhospitable ocean, which are teeming with life. Conspicuous on such “flotsam and jetsam,” as our ancient maritime law-codes term these relics, we mark the Necked Barnacles,[137] so long believed by our ancestors, with a most implicit credence, to be legitimately descended from, and to be in turn the regular and normal parents of, a certain species of goose, common enough on our northern shores. That myth may, however, be dismissed with a mere recollection.

In this form the neck or stalk is greatly developed, frequently reaching to eight inches and upwards in length, with a thickness of half an inch. Externally it is very tough and leathery, yet it is sufficiently flexible to be jerked vigorously in various directions, and thrown into contorted curves, by means of muscles that run through it. The lower part adheres firmly to the support, which is generally wood, and I believe only in a floating condition. The bottoms of ships in warm climates are generally much infested with these parasites, which acquire a great size in the course of a voyage of only a few months.

The valves resemble delicate shells, and are elegantly painted with various tints of light blue varied with white, the edges of the valves being often rich scarlet or orange. The hand is deep purplish black, the fingers stout and massive; but not differing in their structure or in their mode of use, from those of their sessile fellows.

Perhaps the most interesting of all our native forms of these Cirripedes—for true parasitism is always a subject of peculiar interest—is that little species[138] which invariably selects as its support the stony walls of a coral. Our beautiful Cup-coral, so common at extreme low-water level on both the north and south coasts of Devon and Cornwall, is the favourite species of the Pyrgoma. So far as my experience goes, extending over a very extensive series of specimens, I think about one in six of these corals carries the parasite, generally situated either on, or just without, the margin of the cup. I say, “generally,” because Mr. Guyon has lately recorded what he thinks an exception to the rule, in two Pyrgomata situated on the rock close to the base of the coral. But Mr. Holdsworth, an excellent authority, considers that the exception is more apparent than real. The number of these little intruders varies from one upwards. I possess specimens, one of which carries nine, the other eleven; the appearance of the ovate barnacles, each with its conspicuous orifice, crowded all round the edge of the coral, is exceedingly curious and novel. Mr. Holdsworth mentions, however, that he has seen fourteen Pyrgomata attached to a single Caryophyllia, which was dredged in Plymouth Sound.[139]

The transformations of these animals, as investigated by Mr. Darwin, are of great interest. The Cirripede, whatever its genus, and whatever its peculiarities of adult existence, begins its life in a form exactly like that of a young Entomostracous Crustacean, with a broad carapace, a single eye, two pairs of antennÆ, three pairs of jointed, branched, and well-bristled legs, and a forked tail. It casts off its skin twice, undergoing, especially at the second moult, a considerable change of figure. At the third moult it has assumed almost the form of a Cypris, or Cythere, being enclosed in a bivalve shell, in which the front of the head with the antennÆ is greatly developed, equalling in bulk all the rest of the body. The single eye has become two, which are very large, and attached to the outer arms of two bent processes like the letters U U, which are seen within the thorax.

In this stage the little animal searches about for some spot suitable for permanent residence; a ship’s bottom, a piece of floating timber, the back of a whale or turtle, or the solid rock. When its selection is made, the two antennÆ, which project from the shell, pour out a glutinous gum or cement, which hardens in water, and firmly attaches them. Henceforth the animal is a fixture, glued by the front of its head to its support. Another moult now takes place; the bivalve shell is thrown off, with the great eyes, and their U-like processes, and the little Cirripede is seen in its true form. It is now in effect a Stomapod Crustacean, attached by its antennÆ, the head greatly lengthened (in Lepas, etc.), the carapace composed of several pieces (valves), the legs modified into cirri, and made to execute their grasping movements backwards instead of forwards, and the whole abdomen obliterated, or reduced to an inconspicuous rudiment.

Let us resume our grubbing in the heterogeneous heap of matters with which the dredge has enriched us. The tube-dwelling Annelida are generally prominent in such collections, and accordingly we see conspicuous here great and small heaps of contorted tubes, that look as if a batch of tobacco-pipe stems had become agglutinated together, and strangely twisted in the baking. These are the shelly tubes of the beautiful scarlet Serpula,[140] a general favourite in our aquaria, easily and abundantly procured, and readily maintained in health and beauty for a considerable period. I need scarcely describe the general appearance of an object so commonly kept, and so frequently gazed upon. Many tubes are usually found growing together, adhering to the same shell, bit of broken pottery, or small stone; all much intertwined, and mutually adherent, so that it is practically hopeless to attempt to isolate one. Yet by studying many specimens we are able to ascertain that each individual is at first a very slender tube of white calcareous shell, not thicker than sewing-cotton;[141] this rapidly increases both in thickness and in length, soon rising from its support, to which it at first adhered by the lime deposited in a soft state, and continuing the rest of its growth free, in a direction forming various angles with the ground line, and most irregularly twined and contorted. For the final half of its length, or thereabout, the tube attains a diameter of one-fourth of an inch, the walls being sufficiently thick to be solid, yet leaving an ample cavity for the residence of the industrious mechanic, who thus skilfully builds up his own house.

If we carefully break, by a moderated blow with a hammer, the shelly tube, so as not to crush the tenant, we are able to expose the latter to view. We then see that its length is by no means commensurate with the length of its house, of which indeed it inhabits only the last-made portion, having behind a roomy space into which to retire in case of need. It is not more than an inch or an inch and a quarter long, rather wide in proportion, and flattened, with a well-marked distinction between the corslet and the abdomen. The former carries on each side prominent foot-warts, which are vigorously protrusile, and within which bundles of strong bristles are thrust to and fro. On the upper part of each foot, extending half across the back, is a row of microscopic hooks, wielded by long thread-like tendons, which are fixed, on mechanical principles, to the attached end of each hook. By the aid of these, the Serpula so cleverly withdraws with lightning-like rapidity on alarm. By the action of muscles of indescribable delicacy, the hooks are projected to some distance beyond the surface of the body. These organs are formed on the model of a hedger’s bill-hook, only that the edge is cut into long teeth. Carefully counting them I have found that each Serpula carries about 1900 such hooks on its corslet, and that each of these being cut into seven teeth, there are between 13,000 and 14,000 teeth employed in catching the lining membrane of the tube, and in drawing the animal back.

The protrusion of the fore parts, which takes place in a much more leisurely manner, is performed by quite another set of instruments, formed on a totally different principle. Their action is a pushing or shoving. The instruments for effecting this are the fine but strong bristles which run through the feet. Each bristle is composed of a strong rigid unyielding shaft, having an expanded shoulder drawn out into a point. On one side of this pointed shoulder may be remarked a double row of fine teeth, admirably calculated to catch against any roughnesses of the surface with which they come into contact, against which they then push with the force of the proper muscles. Acting diagonally backwards, from the two sides of the animal, the result of the combination of the forces is that the animal itself is pushed forwards, and so protruded from the mouth of the tube. The feet on the hinder portion of the body are, according to Dr. Williams,[142] modified in structure with express reference to the duties of mopping, sweeping, scraping, and wiping the inferior closed end of the habitation. I think, however, he has forgotten that this end, formed by the animal in its infant state, must now be very much too strait to be reached by any portion of the body, or by any of its organs.

Dwelling in a tubular house, the Serpula would find its breathing organs scarcely available, if these were placed, as in most Annelida, in pairs on the body-segments. They are therefore much modified, and that not only in position but in form. They consist of most elegant comb-like filaments, richly coloured, arranged in two rows around the front extremity, one row on each side of the mouth. They are graduated in length, and are so affixed, that, where the rows meet behind, they can be thrown-in, so that a vertical view of the circular coronet shows a great sinus in it. These brilliant gill-tufts form the most attractive feature in these elegant Worms, and are individually most exquisite examples of mechanical contrivance. Examined under a low microscopic power, they present a most charming spectacle. Each filament consists of a pellucid cartilaginous stem, from one side of which springs a double row of secondary filaments like the teeth of a comb. Within both stem and filaments the red blood may be seen, with beautiful distinctness, driven along the artery, and back by the vein (which are placed close side by side) in ceaseless course, constituting a very striking spectacle.

The exterior of these organs is set with strong cilia, so arranged that the water-current is vigorously driven upward along one side of the filament, and downward along the other. Yet the combined result of all the branchial currents is to bring a powerful vortex into the enclosed funnel, the bottom of which terminates in the mouth. The food which sustains nutrition is thus brought to be swallowed, a large quantity of water being at the same time constantly poured into the body; this is discharged (by the agency of a ciliated lining of the hinder parts) in the form of a strong current, which, impinging against the closed end of the tube, is turned upward, carrying with it all extraneous or foecal matters, and is ever pouring out of the frontal extremity around the neck of the creature. What a beautiful and effective contrivance is this for constantly keeping in a state of the most unsullied cleanness the interior of the house! It reminds one of the fabled Hercules cleansing the Augean stable by driving the river Peneus through it.

On each side of the mouth there springs a lengthened horny thread, appearing to answer to the antennÆ which in other Worms, as well as in Insects and Crustacea, project from the front of the head. Such seems their true relation considered structurally, but in function and office they are very remarkable and quite peculiar. To these organs is assigned the duty of closing up the tube when the animal has withdrawn its gaily-coloured plumes; and for this end, one of these antennÆ is much lengthened, and at the end is expanded into a broad trumpet-shaped club, the extremity of which is somewhat concave, and is delicately marked with radiating grooves. This organ is usually painted with the same brilliant colours as the gill-tufts, and by its length, size, and form, makes a very conspicuous feature in the charming Serpula. Its length is such, that when the gill-filaments are rolled up and withdrawn, the conical club enters after all, and is found accurately to fit the trumpet-like orifice of the tube, just as a cork fits tightly into the mouth of a bottle.

Ordinarily those organs which appear in pairs are formed so as to be the counterparts of each other. But here is an exception. One only, sometimes the right, sometimes the left, indifferently, takes the remarkable form that I have been describing, the other being much shorter, and terminating only in a small knob, like the head of a pin. Why should there be this difference? Why this exception to an all but universal rule? The reason is obvious. Yes, obvious enough when seen and noticed; but it tells an eloquent tale of the Divine forethought and care. If both of the antennÆ were furnished with the terminal cone, one would interfere with the other in the performance of their closing, corking-up function; they would jam in the doorway, and the tube would be left open. Hence the one is left undeveloped, yet retaining, as I believe, the latent power of expanding into a cone, if it should ever be needed by the accidental loss of the fellow now so furnished. I thus judge, because experience shows me that the conical club is occasionally thrown off, and quickly renewed, in captivity.

My esteemed friend, the Rev. Sir Christopher Lighton, has indeed put on record an example of a Serpula of this species possessing two equal antennÆ, that had replaced the single one accidentally lost. They were both perfectly developed, and joined together near the base. Each was decidedly smaller than the single one that had formerly occupied their place.[143] This exceedingly interesting case can, of course, only be regarded as a monstrosity of redundancy, as children are sometimes born with a superfluous finger. But it is valuable as showing that there is a power of development latent in the crownless antenna. I wish very much that the excellent observer had added a note, telling us to what extent the tube was closed, and how the work was performed without mutual interference.

It has been sometimes brought as an objection to our assigning a certain service to certain organs, that the necessity for such service is a gratuitous supposition, since other creatures similarly formed in most respects, and in which we might infer a like need, have no such supply. We may admit the facts, but refuse the reasoning. There can be no manner of doubt that the conical antenna does act as a stopper to the Serpula, as our eyes can see; and surely it would be most unphilosophical to suppose that the function so performed is not serviceable to the creature. Yet its near cousins, the SabellÆ, similarly constructed, and of similar habits of life, and as we should have À priori supposed, quite as liable to injury in the same direction, are entirely destitute of this contrivance for protection, and of anything compensating for it, so far as is known. Why the need of one should be met by such a beautiful contrivance, while the same need in the other is wholly unmet, though both are formed by the same Infinite God, is one of those unanswerable questions which, while they leave unimpeached His wisdom, make us deeply conscious of our own ignorance.

We find numerous examples of this genus Sabella in our confused heap of tangled life and death. By their vigour and their abundance we have proof enough that their wants are supplied, though they do not enjoy this special contrivance: they manage to live and thrive and enjoy themselves, with open doors, taking all risks of insidious robbers,—such, for instance, as that vile burglar, the Longworm,[144] that we found under a stone the other day; which is ever on the watch to insert its snaky head within the unprotected tube, and to tear away with merciless clutch the beauteous gill-tufts.

One species of this genus[145] can by the cursory observer be distinguished from the SerpulÆ, only by this absence of the antennal stopper. For it dwells in a shelly tube, essentially resembling those which we have just been examining. It has peculiarities of detail, however. It is never found associated with numbers of its fellows in agglutinated groups, but always, so far as my experience goes, singly. It is more common on shells than on stones, generally attached to the old valve of some cockle or scallop. It is straight or nearly so, never at least contorted. Attached only for a very short portion of its smaller end, perhaps for an inch or so, for which it creeps along the surface, it then rises into a more or less erect position, extending sometimes to a height of seven or eight inches perfectly free. The tube is of about the same diameter as that of the Serpula, but is slighter in structure, or perhaps it appears so, because it is destitute of those expansions which here and there in that species indicate the trumpet-lips of successive stages of development. The extremity of the tube here is simple, not expanding. Slight annular rings, however, do here and there vary the shelly surface of the tube.

The gill-tufts are ample; they are two, considerably infolded, consisting of about forty-five filaments each, which are much longer and slenderer than those of the Serpula, the last filaments of the volutions diminishing rapidly. The secondary filaments, or pinnÆ, are very fine and very numerous, so set on the main stem that the two rows form the sides of a narrow groove, facing inwards. The whole is yellowish-white with eight or ten bright scarlet dots set with intervals all along the back or outer side of the stem. When fully protruded, the base of the gills, and even a good deal of the neck, lolls out of the tube. If the animal be removed, the body is seen to be white, elegantly banded with scarlet, and furnished with a broad translucent collar, edged with scarlet: this collar ordinarily lines the mouth of the tube.

From the length and isolation of its shelly tube this is a remarkable species: the great tenuity of its filaments, however, requires a lens to bring out their beauties; but with this aid, the arrangement of the rich scarlet bands and spots on the pale yellow ground cannot fail to evoke admiration.

In general, the SabellÆ inhabit tubes which are not calcareous or shelly; they are composed of a soft flexible substance somewhat resembling wet parchment, made of a secretion from the animal’s body, in which the impalpable muddy sediment which the waves agitate, consisting of decomposed organic matter for the most part, is interwoven. The tissue so made is sufficiently tough and enduring, retaining its form long after the animal has died out of it.

In our dredge-hauls we find a pretty little kind[146] common enough, which lives in association, the tubes apparently from half-an-inch to an inch in length, forming dense masses on stones and shells, and projecting in every direction. A dozen or more may be in one group, and when all are alive, one or another protruding or retiring every moment, it makes a pretty object.

The gill-filaments are nine to eleven in each row, of a yellowish white, occasionally patched with dead-white, or red-brown: delicately and densely pinnate. The filaments, in the act of protruding, are closed together like a straight bundle of rods which suddenly fall open at the ends. In this moment of unfolding, their tips are seen to be a little hooked inwards. The tube is about as large as a crow-quill; under a lens it appears speckled, as if the inorganic matter imbedded in it were grains of the finest sand. On carefully removing all the surrounding tubes and other objects so as to isolate one, we see that it is truly about three inches in length, but that two-thirds of the whole are prostrate and adherent; this basal portion is horny and pellucid, no mud entering into its texture. The animal when extracted is an inch in length, of which the gill-tufts form one-third.

Mingled with these there are one or two specimens of a much more imposing species, the Hook-plumed Sabella.[147] It grows to a large size, the crown of gill-filaments sometimes attaining a height of an inch, and the same diameter. The two rows are incurved in regular spirals of half a turn, each consisting of about eighteen filaments, which are rather stout, the whole crown sometimes taking the form of a funnel, sometimes that of a cup, often arching inward at the tip. Their pinnÆ are long and close, the two rows forming a groove, but nearly parallel. Each primary stem is set along the back with twelve pairs of feather-like processes, hooked downwards;—a very remarkable character, and one by which this species may be in a moment distinguished. Their colour is pale red-brown, mottled irregularly with deep brownish purple and with white; there is a pair of brown specks at the origin of each pair of hooks. The base of the crown is always concealed in the mouth of the tube, but it springs from a narrow frilled membrane of pure white. The body is destitute of a thoracic shield, or conspicuous collar. The tube is largely composed of soft homogeneous mud, usually of a pale purplish hue, of about the thickness of the shelly tube of S. tubularia.

The process of building the mud tubes of the SabellÆ is a very interesting one. It is performed, according to my own observations,[148] mainly by means of the gill-filaments and their pinnal grooves. The filaments are bent-over, till the inner or grooved face comes in contact with the soft mud on which the animal is lying, when the sensitive pinnÆ close on a minute portion of the mud, taking it up in a pellet, which is then fashioned by the form of the groove; the filament is now erected, and the pellet, passing down the groove to the bottom by means of the cilia, is delivered to the care of two delicate moveable organs, like leaves or flaps, which place it on the edge of the tube, and then shape and mould it, smoothing both surfaces. Doubtless, either from these organs, or from some other part of the circumjacent region, the glutinous secretion is at the same time poured out, which consolidates the mud, and forms the true basis of the tube.