Chapter VII: Part 7

The general colour of the disk is a fine rose-pink, deeper on a circular area in the centre; the network is a deeper rose, especially just around the bases of the knobs. The base of each ray is crossed by a broad band of pure white, both knobs and network. The remainder of the rays is of a pale orange-scarlet, becoming more truly scarlet in the middle portion; the network of the same hue, but deeper. Over the entire surface the areas of the net are occupied by series of ovate whitish hollows, from each of which protrudes a minute clear bladder or closed tube, exactly like those we lately saw in the little Starlet. The madreporic plate is seen about midway between the centre and one of the angles, as a tiny cake-shaped white body, grooved exactly like a brain-stone.

Beneath, the rays are ploughed with a deep groove, in which are two rows of sucker-feet; towards the tip, however, their place is supplied by long slender pointed tentacular processes. The avenues are bordered by flat knobs, set like the edging-stones of a garden walk, each of which carries five or six spines radiating like a fan, _lengthwise_. Each set sends off a branch which carries another fan placed _transversely_, of six to ten spines. Then the white satiny skin sends up at the very edge of the ray short stems, each bearing a group of fifteen to twenty spines, having a tendency to a transverse arrangement, but not in a single row. These form the edges of the rays, seen from above and below. At the bases of the rays beneath, the angle terminates in a broad plate, which is cut into a comb of about eighteen flat spines, the whole having a semi-oval outline, projecting towards the mouth. At the tip of each avenue we discern the little scarlet eye, well protected by the crowding rows of fans.

The mouth gapes, and gives an unexpected insight into the diet of this gaily-painted gentleman. We see a bit of an Echinus shell, and on taking hold of it with a pair of pliers, and carefully dragging, lo! forth comes the entire box of a Purple-tipped Urchin, nearly an inch in diameter, empty of course, through the force of Mr. Sun’s gastric juice, and denuded of spines. Ugh! the cannibal! to eat his own first cousin!

We put him into a shallow pan of water, where he crawls slowly. He is fond of curling the rays over his back, so as nearly to meet, perhaps to have a look at the new world in which he finds himself. Then he turns himself right over in the shallow water, bathing the under surface in the air, the suckers moving all the time to and fro with great rapidity, and (we fancy) with enjoyment.

Several specimens of the common Cross-fish occur, large and richly coloured, and many of the Urchin just named; but these we can find every day in-shore; so they are contemptuously thrown over the gunwale.

GRANULATE BRITTLE-STAR.

Ha! here is a fine thing! It is the Granulate Brittle-star,[114] a species said to be widely spread, but I never saw it before. It is confined to deep water. It is a very fine imposing species, reminding me (a strange comparison, you will say!) of the great South American hairy Spiders, with a brown body and long bristly legs sprawling over a width of eight or ten inches. Its hues are said to be various, but I will describe this as I see it.

The disk is a plump cushion slightly depressed in the centre, of a light reddish umber, or sand-brown. The base of each ray is rich red-brown, the colour encroaching on the disk with two points, and running down the medial line of the ray. This hue is bordered by velvety black, blending with it; and beyond the middle of the ray, the deepening brown is pretty well lost in the black. The ray is edged with spines standing out at right angles, and set in rows. These spines are black with grey points, and greatly augment the noble aspect of the creature. Each ray is about four and a half inches long, running off to a fine point.

The animal resents being turned over, and refuses to lie in a supine position, unlike the “malus pastor” of the poet. It curls and twists the slender ray-tips, crawls rapidly, and courses round and round the edge of the pan into which we have dropped it.

Let me anticipate here to narrate the after history of my captive. Consigned to a shallow tank at home, after a few days I missed him one morning, and on searching the whole room carefully, found him at length under the edge of the hearth-rug, some yards from the tank, with all his rays broken into many pieces, and only the short stumps remaining. Though dry and apparently dead, I perceived a slight movement in the stumps, which gave me hope of revival, and I replaced the poor maimed thing, sadly shorn of his glory, in the tank. He did revive; and the truncated ends of the ray-stumps enabled me to see the arrangement of the spines. These form about nine rows on each side, radiating fan-like; within the undermost row on each side is a row of flexible bladdery tubes much like the suckers, and like them protruding from orifices in the calcareous skeleton, but not retractile. They are studded with tiny warts, and terminate not in a sucking disk, but in a sort of bifid extremity. They are not used for locomotion, nor are they ordinarily applied to the ground as if tactile, and yet are continually thrown round so that the tip is brought up to the base, and this suddenly and abruptly, and every few seconds, as if something were captured and conveyed to the mouth; but this cannot be, for the mouth is not there, and nothing is seen to be seized. Perhaps some intelligence, in a way unimaginable by us, is thus obtained, of outward things.

The poor maimed creature managed to stump awkwardly about for a few days, but soon died, with no perceptible attempt to renew the self-amputated members.

The Brittle-stars appear to move by means of the flexibility of their long snake-like rays, the spines with which they are furnished enabling these organs to obtain a hold on the surface along which they crawl; and that so secure that even perpendicular and very smooth surfaces present no hindrance to their progression. They have no proper suckers; and the rays are not constituent portions of the body, containing part of the stomach and intestine as in the true Star-fishes, but imperforate appendages to it.

ANGLED CRAB.

Crouching among the rubbish, with all its long limbs snugly packed together, as if hoping to find safety in being overlooked, we see a strange form of crustacea, the Angled Crab.[115] Vain hope! How can a creature of that bizarre form, and of those conspicuous colours, be concealed from notice by merely lying still? Gently touch him behind, and what an enormous length of limb is suddenly thrown out! If, according to the proverb, “kings have long arms,” surely this must be the very monarch of the crabs; and most curiously are they folded when at rest, the fore-arm lying close, throughout its length, upon the upper arm, the elbow projecting far on each side. The carapace is sometimes described as rhomboidal, but this does not give us a correct idea of its form; its outline is rather that of an isosceles triangle, of which the apical half is cut off; the base of this truncate triangle, which is the front side of the shell, runs off into two sharp spines at the angles, and has also a broad projection in the middle, on each side of which are seated the long footstalks of the eyes, and which carries on its front the two pairs of antennæ. The thighs of the true legs are thin and blade-like, so that these limbs all pack one over the other very compactly.

PLATE 26.

P. H. GOSSE, _del._ LEIGHTON, BROS.

NUT-CRAB. ANGLED-CRAB.
]

The general colour is a light salmon-red, often with the hinder half of the carapace, and the inner sides of the limbs, of a pale buff. The eyes (not the stalks) and the movable finger of each hand, which is slender and elegantly curved, are polished black.

Not uncommon with us, it is not very often seen even by the naturalist, as it seems to be properly an inhabitant of deep water. Occasionally it is washed ashore on the beach by a heavy sea; but this is accidental. Montagu first ascertained it to be British by finding it at Kingsbridge, near Plymouth. Mr. Couch finds it common on the Cornwall coast, together with an allied, but certainly distinct, species, the _G. rhomboides_ of the Mediterranean, to be identified by its lacking a second spine behind each angular one, which is well marked in our species. Though essentially a southern form, it occurs on the Dublin coast, and that in sufficient number to have obtained a popular appellation,--that of “Coffin-crab;” the term “coffin” being possibly a word of the Irish tongue, meaning something very different from that which it suggests to our ears.

Cranch records, as a curious habit of the species, that “they live in excavations formed in the hardened mud, and that their habitations, at the extremities of which they live, are open at both ends.” This description implies a habitat above low water, if not above tide-marks; for where else could “hardened mud” be found? or if it were found in the deep water, how could it come under the observer’s cognizance? However, I know that many marine creatures are littoral in some localities, which are exclusively deep-water subjects in others.

Several observant naturalists have noticed the frequency with which the species is obtained from the stomachs of the larger ground-feeding fishes,--the cod especially. Mr. Ball has taken four at a time from a single cod in Youghal shambles. This is a well-known source for procuring rare specimens of the inhabitants of the deep, particularly Crustacea and the shelled Mollusca; for the fishes are expert and persevering and successful collectors of natural history, and are continually picking up objects for which the naturalist would almost give one of his eyes. Mr. Gordon of Elgin, some years ago, gave a long list of Crustacea, many of them of great rarity, which he had procured from stomachs of cod-fish, “through the agency of Widow Scott and her son John, of the fishing village of Stotfield,” on the Moray Firth. His remarks are suggestive, not only to those residing on the coast, but to the denizens of inland towns. “By a small douceur to the fisherman’s family, and by the assistance of the fish-curer on the coast, the fishmonger of the large town, or of some acquaintance in the fishing village, it is believed that almost any number of these now useless receptacles [viz., cod-stomachs], could be obtained. It may excite at first a little nausea to open up and examine these omnivorous reservoirs, but this will soon pass off; and were it of longer continuance than it is, the stores to be unfolded would amply compensate for all the disagreeable feeling that may for a time arise. It is not only the crustacean that is thus gathered from the inaccessible depths of the ocean, but often the rare shell, with its still rarer inhabitant. The radiated animal and the curious zoophyte will also be found congregated together there; all of them, no doubt, at times mutilated or partly digested, but not unfrequently fresh and complete, as if newly past the voracious jaws.”

NUT-CRAB.

Two or three specimens of another curious crab are also in our haul. Unlike the _Gonoplax_, the little Nut-crab[116] is not by any means conspicuous in a chaotic heap like this; it requires a sharp eye, and one familiar with the form, to discern him. Remarkably sluggish, he remains motionless; his tiny limbs are almost concealed under the edges of his shell; his body is destitute of sharp angles; its colour is a dull white: in fact the eye might roam over it a dozen times without supposing it anything more than an irregular rubbed quartz pebble.

Yet when you pick it up, it is a pretty little Crab. The form of the body is unlike that of any other of our genera; indeed the type of which it is a representative, though largely developed in the tropical and sub-tropical seas, scarcely reaches to our shores. Some of the allied species in the hotter parts of the globe, are very curious, such as the _Calappa_, a crab in which the very short limbs are so closely packed to the body, and so wholly concealed by the smooth and rounded shell, that the curious sailor often picks it up and pockets it, as a pretty white stone, little suspecting that he has a living Crab in his fob. And there it lies for hours, perhaps, till he pulls out his supposed pebble, which has not ventured all the while to attempt to crawl.

I believe almost all we yet know of the habits of the timid little Nut-crabs is derived from the portrait that I drew of one of them[117] some years ago, from specimens that I obtained at Weymouth. Since then I have repeatedly kept it in captivity for long periods at a time, and indeed I have one or two now. Yet I have little to add to the sketch I then drew of its manners. It is inert, folding its tiny legs on itself when touched, and remaining motionless for some time. It buries itself in the gravel, descending backwards: this is a somewhat slow process, suited to its usual phlegmatic habit. It brings its hindmost pairs of feet on each side together; then thrusting down their united points, opens and expands them, forcing apart the gravel; at the same moment the posterior part of the body is brought down into the hollow thus made, and the action of the feet is repeated. The process is continued until the hinder parts are covered and the muzzle alone is visible, with the two claws. Thus it sits quite still, reminding one of a toad, the broad triangular pedipalps that fit so close occasionally opening, like the folding-doors of a tiny cabinet, and allowing the palpi to be thrust out to wipe the minute eyes. The face, when examined with a lens through the glass walls of the aquarium, has a most funny expression, being singularly like that of an ancient man.

Like many marine animals, _Ebalia_ uses the hours of the night as its chief season of activity. As long as the candles are in the room, it remains pretty still, but as soon as darkness reigns, it sets out on its travels. Not indeed with the railway pace of some of its fellows does our little ancient travel; he is but a “slow coach;” but he gropes about among the pebbles, and is usually found the next morning, buried at some distance from the point where the previous evening had left him.[118]

BRYER’S NUT-CRAB.

The little specimens before us appear to belong to _Ebalia Bryerii_. It is porcellaneous white, tinged with pale scarlet. The little feet are painted scarlet on a white ground, especially the swollen-jointed claws, which are very gay, and under a lens show a marbled pattern of rich scarlet. This little Crab has an unique appearance, very attractive. Its motions are quick and sudden, mostly lateral, when alarmed; but it is habitually sluggish. Sometimes it appears to sham death; for if pushed, it at first tries to escape by running; but if the annoyance continues, it stiffens its limbs, and allows itself to be pushed without resistance; and when laid on its back in the water, will lie motionless for a minute or more, then suddenly turn over and crawl away.

Hosts of other things we capture in this summary sweeping of the sea-bottom, and by the time we have drifted down towards the Orestone, till we are close enough to make out the noble leaves of the tree-mallows that grow out of its rocky heights, we have accumulated a marvellous store,--almost enough, indeed, to set up a little provincial museum. Brittle-stars and urchins; cucumbers great and small; bivalve and univalve mollusks; swollen ascidians, smooth and warty; active, shuffling, sucking fishes; heaps of mossy _Bryozoa_; long bristling tufts of Hydroid zoophytes; naked worms, twining and writhing amidst the mass, gleaming in purple and pearl; sea-mice “armed in gold,” like Virgil’s Orion; tangled masses of Serpula-pipes, every one with its scarlet-crowned tenant; these, and multitudes of creatures besides, come up from the teeming sea-floor, and all at once claim our bewildered attention. And there is not one of the host that is not worthy of it; not one that would not be an eloquent witness of its Creator’s glory; but we must for the present neglect them all (not without hope of another meeting with some of them at least), in order to devote a few moments to one group of remarkable interest.

It is that unaccountable association of diverse and unrelated creatures, which, if we had not repeatedly seen it, we should not believe; the companionship of the Hermit-crab with the beautiful Cloak-anemone.

HERMIT-CRAB AND CLOAKLET.

Every one is familiar with that impudent and intrusive species of Hermit-crab,[119] which, with its foxy-brown head and legs protruding, rolls over shells and pebbles with rattling patter, on almost every beach. The species I speak of is quite distinct from that homely and amusing subject. Though attaining a size fully equal, its proportions are much slenderer and more elegant; and the colours,--a light fawn, set off with soft tints of azure, lilac, and scarlet,--are far more beautiful than those of its fellow; not to speak of technical characters which abundantly distinguish the two.

The companion of the Cloaklet, which bears the name of Mr. Prideaux of Plymouth, who first made it known, is exclusively a deep-water species. Found on various parts of our coast, it invariably occurs in this association. I believe the Crab in no instance lives without the Anemone, the Anemone in no instance without the Crab. Examples, indeed, do now and then occur, as mentioned by Forbes, in which the one comes up in the dredge without the other; but I believe this is only when the rude action of the dredge has frightened the Crab, and induced it suddenly to vacate the shell and desert its friend. The Bernard is never attended by any such companion.[120]

The history of the tenancy of univalve shells by these curious Crabs is well known; and the comic scenes that take place in the process of flitting from one tenement to another, larger and more commodious, have been so fully narrated by myself and other observers, that I shall assume the reader to be conversant with them.[121] And the rather because the association of the Crab with the Zoophyte is a thing so much more singular, so much more unaccountable, and so much less generally known, that I shall seek to tell the story in some detail.

PLATE 27.

P. H. GOSSE, _del._ LEIGHTON, BROS.

PURPLE HERMIT-CRAB. CLOAKLET. COMMON HERMIT-CRAB.
]

HERMIT AND CLOAKLET.

To premise:--the Cloaklet is an anemone of the _Sagartia_ family, beautiful in its colours and remarkable in its form. It is generally reddish-brown on the outer (lower) part of its body, which hue melts into snowy white on the upper parts; the whole studded with rosy-purple spots, and surmounted by a marginal line of pale scarlet. The tentacles and disk are pure white. It attains a rather large size, and has the peculiarity of being not round in its basal outline like other Anemones, but oblong, the base expanding in two lateral directions. It always selects the inner lip of an univalve shell for its place of adhesion, and the two lateral ends of its base gradually extend around the mouth of the shell till they meet on its outer edge, and unite with a suture: thus the outline of the animal forms a ring.

It had often been an interesting speculation with me, in what manner the due relation of size is maintained between the _Adamsia_ and the shell, in the progressive growth of the former. There is a manifest proportion between the two, the young Cloaklet occupying a small shell, such as that of a _Littorina_ or _Trochus_; the full-grown individual a large one, such as that of a _Natica_ or _Buccinum_. The Crab is able to shift from a smaller to a larger shell when he needs enlarged accommodation; and since we know that his congener, _P. Bernhardus_, does this habitually, we naturally conclude that such is the habit of _P. Prideauxii_. Presuming then that this is the case, what becomes of the _Adamsia_? If the Crab shifts his quarters and leaves the _Adamsia_ behind, the association is broken, and we should constantly find _Paguri_ without _Adamsiæ_, and _Adamsiæ_ without _Paguri_. But we find neither the one nor the other.

On the other hand, if _Adamsia_ is able to shift its quarters also, how does it proceed in its search for a new shell? If it forsakes the old tenement at the same time as the Crab, and together with it takes possession of the new one, by what means is unity of will and action secured? What communication of thought takes place from the one to the other? As the _Adamsia_ does not adhere to the Crab, but to the shell, that is, as they are independent of each other’s movements, who takes the initiative? Who goes to seek the lodging? And at what point of the transaction does the other come in? All these questions I had mused upon with interest; and at length received some light towards their solution.

On the 10th of January, 1859, I obtained, by dredging, in Torbay, a specimen of _Adamsia palliata_, about half-grown, on a rather small shell of _Natica monilifera_, tenanted by a _Pagurus Prideauxii_, which seemed already too big for his habitation. Having put them into a well-established tank of large dimensions, the contents of which were in excellent condition, I succeeded in doing what I had never done before, domiciliating both Crab and _Adamsia_. Both continued in the highest health, and became quite at home.

After about three months, however, I noticed that the _Adamsia_ was not looking so well. One side or wing had gradually loosed its hold of the shell-lip, so that it hung loosely down beneath the breast of the Crab. Yet in other respects the zoophyte seemed healthy. Latterly, too, the Crab had manifested symptoms of uncomfortable straitness, in the great extrusion of his fore-parts; so great, indeed, as to expose even the front of the soft abdomen. Yet I felt reluctant to present to the Crab a larger shell, fearing that he would, in availing himself of it, desert his zoophyte friend, which would then die, and I should lose the specimen.

At length the desire to solve a problem in science prevailed over this feeling. A fact is better than a specimen. And so (on April 21st) I selected from my cabinet a full-grown _Natica_ shell, and placed it on the tank-floor, not far from the disconsolate trio.

The _Pagurus_ presently found the new shell, and immediately began to overhaul it. He did not do, however, as his brother Bernhard would have done, at once shift into the new house. Having turned it mouth upward, he took hold of the outer and inner lip, each with a claw, and began to drag it about the tank. Occasionally he relinquished the hold of one claw, and probed the interior in the usual manner, and then resumed his march. I watched the proceedings for an hour or more, when, having other work to do, I left him alone.

The thought did occur to me--Can this delay be intended to make the _Adamsia_ cognizant of what is in contemplation, and to prepare it for the change? But I dismissed it as unlikely.

After about an hour’s absence I returned to the examination. The _Pagurus_ was comfortably lodged in his new abode, and the old one, which now looked small indeed, lay deserted at some little distance. I eagerly turned the latter over, to see what was the condition of the _Adamsia_. Lo! no _Adamsia_ was there; and the _Pagurus_, presently approaching the front of the tank, I saw, to my great gratification, that the old association was unbroken. There was the _Adamsia_, with one wing adhering to the lip of the new shell, and apparently the opposite wing also; but, from the position of the group, this I could not be quite certain of. The situation of the zoophyte was quite normal,--the centre immediately below the breast of the Crab, and in contact with the inner lip of the shell, while that wing which I could clearly see was creeping round upon the outer lip.

Examining now more closely the condition of things, with a lens, I saw that the central part of the _Adamsia’s_ base was adherent by a small point of its surface to the under side of the thorax of the Crab, between the bases of the legs.

Now this adhesion to the Crab is a circumstance which, so far as I know, never takes place in the ordinary relations of the animals; and therefore I could not but think it an extraordinary and temporary provision for the removal of the _Adamsia_ from the old to the new shell, and for the correct adjustment of its position on the latter.

How then can we avoid the conclusion, that, as soon as the Crab had found the new shell to be suitable for exchange, the _Adamsia_ also was made cognizant of the same fact; and that, during the two hours which followed, the latter loosened its adhesion to the old shell, and, laying hold of the bosom of its protector, was by him carried to the new house, where immediately it began to secure the like hold to that which it had just relinquished?

Eleven days elapsed after the above observations were made, when I obtained another interesting fact bearing on this strange association. The _Adamsia_ had not looked well since the change of residence; its adhesion to the shell had been but partial at the best, some days more, some days less, extensive; but for the most part a considerable portion of the zoophyte was hanging down from the shell. The Crab, on the other hand, was evidently in clover, and showed no inclination to go back to his old lodging.

On the 2d of May I found the _Adamsia_ detached, and lying helpless on the bottom of the tank, beneath the Crab, who, when disturbed, walked off, leaving his companion behind. I thought now it was a gone case, and that it was all up with my elegant _protegée_.

An hour or two afterwards, however, how great was my surprise to see the _Adamsia_ fairly established again, adhering to the shell by a good broad base, and looking more healthy than I had seen her for many a day! Strangely enough, she was adhering in a false position, having taken hold on the outer lip of the shell, instead of the inner, as usual. Here was a fresh proof of intelligence somewhere; and I at once set myself to find where.

Carefully taking up the shell with the aquarium-tongs, and bringing it close to the surface, but not out of water, I gently dislodged the _Adamsia_ with my fingers, and allowed it to fall prone upon the bottom. I then released the shell with its tenant, and drove the latter towards the spot where the zoophyte lay.

No sooner did the Crab touch the _Adamsia_ than he took hold of it with his claws, first with one, then with both, and I saw in an instant what he was going to do. In the most orderly and expert manner he proceeded to apply the _Adamsia_ to the shell. He found it lying base upward, and therefore the first thing was to turn it quite round. With the alternate grasps of the two pincer-claws, nipping up the flesh of the _Adamsia_ rudely enough, as it seemed, he got hold of it so that he could press the base against the proper part of the shell, the inner lip. Then he remained quite still, holding it firmly pressed, for about ten minutes; at the end of which time he cautiously drew away first one claw, and then the other; and, beginning to walk away, I had the pleasure to see that the _Adamsia_ was once more fairly adhering, and now in the right place.

Two days after the _Adamsia_ was again lost. On searching I discovered it lying in a crevice, whence I plucked it, and laid it on the bottom. Here again the Crab found it, and immediately went through the same process as last described, and again made it adhere. But I saw that the _Adamsia_ was unhealthy, for it seemed to have but enfeebled power of retaining its hold. The manifestation of the mode in which the instinctive actings of the two creatures occur is, however, sufficiently clear. The Crab is certainly the more active promoter of the partnership; it is abundantly evident that he values the company of his elegant but very heterogeneous associate. These last observations compel the conclusion that the claws of the Crab are always employed in the transference of the Cloaklet from shell to shell.[122]

PROOFS OF INTELLIGENCE.

But what a series of instincts does this series of facts open to us! The knowledge by the Crab of the qualities of the new shell; the delay of his own satisfaction till his associate is ready; the power of communicating the fact to her; the power in her of apprehending the communication; her immediate obedience to the intimation; her relinquishment of her wonted hold, which for months at least had never been interrupted; her simultaneous taking of a new, unwonted hold, where alone it could have been of any use; the concerted action of both; the removal; her relinquishment of the transitory adhesion as soon as its purpose was accomplished; her simultaneous grasp of the new shell in the proper places; all these are wonderful to contemplate, wonderful considered singly, far more wonderful in their cumulation. Is there not here much more than what our modern physiologists are prone to call automatic movements, the results of reflex sensorial action? The more I study the lower animals, the more firmly am I persuaded of the existence in them of psychical faculties, such as consciousness, intelligence, will, and choice! and _that_, even in those forms in which as yet no nervous centres have been detected.

FOOTNOTES:

[113] _Solaster papposa_, represented, about one-third of the natural size, by the right-hand figure on Plate XXV.

[114] _Ophiocoma granulata_, seen in the upper left-hand corner of Plate XXV.

[115] _Gonoplax angulatus_, the principal figure in Plate XXVI., occupying the foreground.

[116] _Ebalia_; a male specimen of _E. Bryerii_ is represented in Plate XXVI., clinging to the stem of an aged tangle, in the upper left-hand corner.

[117] _E. Pennantii._

[118] _Aquarium_ (2d Ed.), p. 154.

[119] _Pagurus Bernhardus_; so called, I presume, from Bernard, the monk, in allusion to its passing its life in its cell: whence also “Hermit-crab.”

[120] In Plate XXVII. both species are represented. In the foreground is a full-grown _Pagurus Prideauxii_ tenanting a whelk-shell, which carries a fine specimen of the Cloak Anemone (_Adamsia palliata_). In the distance is seen _P. Bernhardus_, inhabiting a shell of _Natica_.

[121] See my _Aquarium_, p. 156, _et seq._

[122] These facts were originally published in the _Zoologist_ for 1859 (p. 6580). In the _Quarterly Journal of Science_ for January 1864, some observations of Colonel Stuart Wortley are cited, confirmatory of mine, which, however, are wholly ignored by the Editors.

X.

OCTOBER

PORTUGUESE MAN-OF-WAR.

The naturalist who has occasion to make a voyage over the warmer regions of the ocean, is continually delighted by the sight of numberless forms of animals, principally of the lower invertebrate classes, which either habitually swim at the surface of the sea, or come thither at intervals to enjoy the stimulus of the atmospheric air. Many of these are exceedingly curious and interesting; many totally unlike any forms that occur on the shores of temperate countries; many elegant in contour, and adorned with brilliant colours. Perhaps there is scarcely any that takes a stronger hold on the fancy, certainly none is more familiar, than a little thing that he daily marks floating in the sunlit waves, as the ship glides swiftly by, which the sailors tell him is the Portuguese man-of-war.[123] Perhaps a dead calm has settled over the sea; and the observer, as he leans over the bulwarks of the ship, has opportunities of scrutinizing the ocean-rover at leisure, as it lazily rises and falls on the long sluggish heavings of the glassy surface. Then he sees that the comparison of the stranger to a ship is a felicitous one; for, at a little distance it might well be mistaken for a child’s mimic ship, shining in all the gaudy painting in which it came out of the toy-shop; and he is ready to pity the forlorn urchin in tunic and knickerbockers, whose cherished boat has broken her moorings of thread, and drifted with winds and tides far, far out of reach of land.

PLATE 28.

P. H. GOSSE, _del._ LEIGHTON, BROS.

PORTUGUESE MAN-OF-WAR. TONGUED SARSIA.
]

Not unfrequently does one of the tiny vessels come so close alongside that, by means of the ship’s bucket, with a little assistance from a smart fellow, who has jumped into the “chains” with a boat-hook, it is captured, and brought on deck to be subjected to scientific examination. A dozen voices are however lifted, warning you by no means to touch it, for well the experienced seaman knows its terrific powers of defence. It does not now appear so like a ship as when it was at a distance. It is an oblong bladder of tough membrane, varying considerably in shape (and hence no two original figures agree in this respect), and also in size, from less than an inch in length to the size of a man’s hat. Once in a voyage to Mobile, when rounding the Florida Reef, I was nearly a whole day passing through a fleet of these little Portuguese men-of-war, which studded the smooth sea as far as the eye could reach, and must have extended for many miles. These were of all sizes within the limits I have mentioned. Generally, there is a conspicuous difference between the two extremities of the bladder, one end being rounded, while the other is more pointed, or is terminated by a small knob-like swelling, or beak-shaped excrescence, where there is a minute orifice. Sometimes, however, no such excrescence is visible, and the orifice cannot be detected.

The bladder is filled with air, and therefore floats almost wholly on the surface. Along the upper side, nearly from end to end, runs a thin ridge of membrane, which is capable of being erected at the will of the animal to a considerable height, fully equal at times to the entire width of the bladder, when it represents an arched fore-and-aft sail, the bladder being the hull. From the bottom of the bladder, near the thickest extremity, where there is a denser portion of the membrane, depends a crowded mass of organs, most of which take the form of very slender, highly contractile, and moveable threads, which hang down into the deep to a depth of many feet, or even occasionally, of several yards.

THE BLADDER.

The colours of this curious creature are very vivid: the bladder, though in some parts transparent and colourless, and in some specimens almost entirely so, is in general painted with the richest blues and purples, mingled with green and crimson to some less extent; these all being, not as sometimes described, iridescent or changeable reflections, but positive colours, independent of the incidence of light, and, for the most part possessing great depth and fulness. The sail-like erectile membrane is transparent, tinted towards the edge with a lovely rose-pink hue, the colours arranged in a peculiar fringe-like manner.

When examined anatomically, the bladder is found to be composed of two walls of membrane, which are lined with cilia, and have between them the nutritive fluid which supplies the place of blood. Besides this, the double membrane is turned in, somewhat as the foot of a stocking is inverted, when ready for putting on; and thus there is a bladder within a bladder, both having double walls. The inner (_pneumatocyst_) is much smaller than the outer (_pneumatophore_); and the point where it is turned in is contracted to the almost imperceptible orifice that has been mentioned. The inner bladder sends up closed tubular folds into the crest, which, being invested by the membranous walls of the outer sac, give to the sail that appearance of vertical wrinkles which is conspicuous.

EFFECTS OF POISON.

Most formidable are the powers which reside in the long tentacles. Each of these is an excessively slender ribbon of contractile substance, connected at its base with a translucent bag, and carrying at short intervals throughout its length semi-rings of thread-cells (_cnidæ_), similar to those of our Sea-anemones, but of far more deadly virulence. Mr. Bennett, who, for the sake of science, ventured to test their powers, has left us a terrific account of his sufferings. “On one occasion,” he says, “I tried the experiment of its stinging powers upon myself, intentionally; when, on seizing it by the bladder portion, it raised the long cables by muscular contraction of the bands situated at the base of the feelers, and, entwining the slender appendages about my hand and finger, inflicted severe and peculiarly pungent pain, adhering most tenaciously at the same time, so as to be extremely difficult of removal. The stinging continued during the whole time that the minutest portion of the tentacula remained adherent to the skin. I soon found that the effects were not merely confined to the acute pungency inflicted, but produced a great degree of constitutional irritation: the pain extended upwards along the arm, increasing not only in extent but in severity, apparently acting along the course of the absorbents, and could only be compared to a severe rheumatic attack; the pulse was accelerated, and a feverish state of the whole system was produced; the muscles of the chest even were affected, the same distressing pain felt on taking a full respiration as obtains in a case of acute rheumatism. The secondary effects were very severe, continuing for nearly three-quarters of an hour; the duration of the pain being probably longer, in consequence of the time and delay occasioned by removing the exciting and virulent tentacula from the skin, as they adhered to it, by the aid of the stinging capsules, with an annoying degree of tenacity. On the whole being removed, the pain began gradually to abate; but during the day a peculiar numbness was felt, accompanied also by an increased temperature in the limb upon which the stings had been inflicted. For some hours afterwards the skin displayed white elevations or wheals on the parts stung, similar to those usually seen resulting from the poison of the stinging-nettle. The intensity of the pain depends in some degree upon the size and consequent power of the creature; and after it has been removed from the water for some time, the stinging property, although still continuing to act, is found to have perceptibly diminished. To remove the irritation, at first cold water was applied, but this, instead of alleviating, increased the evil: an application of vinegar relieved the unpleasant symptoms, and olive oil has produced a similar beneficial effect. I have observed that this irritative power is retained for some weeks after the death of the animal in the vesicles of the cables; and even linen cloth which had been used for wiping off the adhering tentacles, when touched, still retained the pungency, although it had lost the power of producing such violent constitutional irritation.”[124]

Among the tentacles there are seen many depending organs, which take somewhat the shape of a claret-bottle, with the mouth a little expanded. These are highly moveable, turning and bending themselves in various directions. They are termed _polypites_, and are the mouths and stomachs of the animal: taking-in and digesting food, much as the protrusile lips of an Anemone do. Mr. Bennett describes the _Physalia_ as seizing and benumbing small fishes by means of the tentacles, which are alternately contracted to half-an-inch, and then shot out with amazing velocity to a length of several feet, and which drag the helpless and entangled prey to the sucker-like mouths, the stomach-cavities of which were filled while he looked-on, with atoms of the flesh absorbed.

Dr. Wallich thinks Mr. Bennett must have mistaken what he saw; because he has observed that in a great number of cases the _Physalia_ is accompanied by small fishes, which play around and among the depending tentacles without molestation. He has in so many cases seen this, and even witnessed the actual contact of the fishes with the tentacles, with no inconvenience to the former, that he too hastily concludes that “the urticating organs are innocuous.” Surely the premises by no means warrant such an inference. There is no antagonism between the two series of facts witnessed by such excellent observers; the venomous virulence of these organs has been abundantly proved by many naturalists, myself among the number, and Mr. Bennett, to his cost, as narrated above. We have only to suppose that the injection of the poison is under the control of the _Physalia’s_ will, and the impunity of the bold little fishes is sufficiently accounted for.

THE GULF-STREAM.

That wonderful river that flows with a well-defined course through the midst of the Atlantic,--the Gulf-stream,--brings on its warm waters many of the denizens of the tropical seas, and wafts them to the shores on which its waves impinge. Hence it is that so many of the proper pelagic creatures are from time to time observed on the coasts of Cornwall and Devon. The Portuguese man-of-war is among them, sometimes paying its visits in fleets; more commonly in single stranded hulks. Scarcely a season passes without one or more of these lovely strangers occurring in the vicinity of Torquay; and from one of these I took the opportunity of making the careful drawing with which I illustrate this paper.[125] The fishermen and similar persons who pick them up, always endeavour to make a harvest of their captures, not by the sale, but by the exhibition of them, sometimes carrying the specimen from door to door, sometimes erecting a temporary screen in some place of resort, exaggerating the rarity and value of the specimen outrageously. This summer (1862) I have known of three in this vicinity; and have heard of one at the Isle of Wight, in July, which forms the subject of a memoir and a coloured figure by Mr. Humphreys in the _Intellectual Observer_; also, a fleet of hundreds scattered over both sides of the same island in August, as recorded by Mr. Rogers in the _Zoologist_; and finally, one at Tenby in July, obtained by Mr. Hughes, and recorded in the last-named periodical.

Mr. Hughes in his account mentioned a circumstance as normal, which, being unknown to me, excited my curiosity. His specimen was accompanied by “its attendant satellites, two _Velellæ_.” In reply to my inquiries my friend gives me the following information:--“My authority for the association of Velella with Physalia is Jenkins, the collector at Tenby, who was attending me when they were found.

“The Physalia was taken by me first; and, while I was admiring it, I noticed that Jenkins continued searching for something. Immediately afterwards he came up with the Velella in his hand, at the same time stating they were generally found with the Portuguese man-of-war. As I had found the man very honest and truthful in his dealings with me (and not previously being familiar with either of the creatures), I accepted the information as correct.”

VELELLA.

The _Velella_ is a creature closely allied to the _Physalia_, having the same essential structure, but differing greatly in form and appearance. It consists of a flat disk of thin cartilaginous shell, of a long rectangular outline, on which stands erect another similar plate somewhat triangular, extending across from corner to corner. One large polypite or mouth hangs down from the centre of the under side, and short tentacles project on all sides from the edges of the horizontal plate. The internal structure is very complex. The whole is enclosed in a thin layer of flesh, which is tinged of a fine blue colour, sometimes varied with purple and green. It is generally about two inches long, and the erect plate rather less in height. As the little creature floats on the waves, this plate forms a sail, and the breeze playing upon it, imparts to the whole animal, according to Mr. Bennett, a rotatory motion.[126]

STEPHANOMIA.

Both these oceanic forms of the class _Hydrozoa_ agree in being quite unprovided with any apparatus for locomotion. Though their parts can be moved among themselves, and sometimes with much vigour, as we have seen in the case of the tentacles of the _Physalia_, yet the whole organism would be absolutely confined for life to one spot, were the elements motionless around it: it is merely passively driven hither and thither by the winds and waves. But there are other members of the class, and even some belonging to the same order, which have express organs of locomotion. A most exquisite example is found in _Stephanomia_, of which a specimen was taken in Kingstown harbour in July 1856, by Mr. Joseph Greene, and described and figured in the “Proceedings of the Dublin University Zoological Association” for that year. The float (_pneumatocyst_) is a small bladder, which is filled with air, and which has the appearance, when alive, of a globule of quicksilver; while the slight inequalities of its surface reflect the light in such a manner that it often looks as if a fine network of crimson veins ramified over its surface. From the end of this oval bladder a long fleshy tube hangs down in the water to the distance of six or seven inches, the upper part of which is surrounded by a number--seven to ten--of little clear transparent bells, looking very much like the blossoms of our common Arbutus, and crowded, like flowers with short footstalks, on the stem. These swimming bells (_nectocalyces_) are true organs of locomotion; for by their contraction they drive out the water contained in their cavities, and by their combined impulse, all acting together, shoot the whole creature forward. This action I will explain more in detail presently.

The long tube or common stem is very irritable, and under stimulus is coiled up in a spiral, then gradually relaxed, and allowed to hang loosely down. Attached to it throughout are the _polypites_, or stomach-mouths, protected by leaf-like organs, which overlap them. Numerous tentacles, too, of exceeding length and tenuity, and throwing off branches, spring from the stem throughout its length, all the extremities of each forming tiny oval knobs of spiral coils, the whole capable of being thrown into the most beautiful and graceful convolutions, now bent at right angles, and again thrown out in a series of light airy-looking arches.

The exquisitely beautiful specimen described was taken in sultry weather, when the sea was perfectly calm. “It lived in a large globe of sea-water for several days, and was a most striking and beautiful object: it generally lay quite upright in the water, the slightest ripple upon the surface of which set it in motion; and immediately coiling up its fishing lines, and shortening the length of its stolon by about one-third, it threw its set of little balloons into strong pulsations, until, weary of descending, it submitted to be guided by its brightly glittering head, and soon ascended to the surface. When subjected to examination it soon died, and was not long until it had completely broken itself up.”[127]

SARSIA.

The _nectocalyx_ or swimming-bell is, however, seen in a much more developed condition in the delicate forms which swarm in our harbours and about our rocky coasts in summer and early autumn, and are known by the name of Naked-eyed Medusæ. A common and very characteristic example of this order is the Tongued Sarsia,[128] in which a single swimming-bell forms the greatest portion of the whole creature. It is a tall dome of crystalline colourless flesh, thick at the summit and thinning off at the edges; about half an inch in height. From the interior of this dome hangs the single polypite, exactly as the clapper hangs from the top of a bell. It is long and cylindrical, abruptly attenuated at the upper part into a sort of foot-stalk, and at the extremity enlarging into four fleshy, very protrusile, lips, capable of seizing and sucking in an object much larger than the diameter of the whole polypite. I have seen a Sarsia, in confinement in a tank, lay hold of, and swallow, a newly-hatched fish, notwithstanding the activity of the latter. For hours afterwards the little green-eyed fry was visible, the engulphment being a very slow process; the Medusa, however, never let go its hold; and gradually the tiny fish was sucked into the interior, and passed up the cavity of the polypite, becoming more and more cloudy and indistinct, as digestion in the stomach gradually dissolved its tissues.

These little creatures are endowed with very effective powers of locomotion. In the unbounded freedom of their native sea, and in the limited dimensions of a glass vase, they are alike sprightly. By rapid pump-like contractions of their _nectocalyx_, they dart through the water, and shoot round and round, almost with the force and swiftness of a swimming fish. The summit of the bell always goes foremost, whether the direction of the movement be vertical, horizontal, or, as is most commonly the case, oblique; and the tentacles, and the long white polypite, drag behind in trailing lines. Now and anon, the shooting is suddenly suspended, the bell hangs over and remains awhile motionless, the tentacles are allowed to depend like spiders’ webs, or are suddenly drawn up into shrivelled puckers, become mutually entangled and intertwisted, then slowly free themselves, and hang down again. Sometimes the motionless bell itself sinks very gradually, and the tentacle-threads take the most elegant curves and arches in their descent.

The manner in which the strong pulsating movements of the Medusæ are performed depends on the position and action of certain bands of muscular tissue. Four of these radiate from the centre of the dome to the margin. This course is not a straight but a curved one. When, therefore, these bands are simultaneously and forcibly contracted in length, they are drawn from a curved into a straight line, and the cavity, which was bell-shaped, becomes more conical, and its capacity is considerably diminished; a portion of the water which it before held is therefore driven out at the mouth, and by its reaction forces the animal forward with a jerk in the opposite direction. Besides these radiating muscles, there are circular bands which pass round the margin and the interior walls of the dome. These by their contraction diminish the volume of the cavity, and aid the action described above.

FORBES’S ÆQUOREA.

The tiny Sarsia has but four tentacles, which spring from as many equidistant points on the margin of the bell. But in the genus _Æquorea_, of the same family, these organs are far more numerous, two species which I first discovered at Ilfracombe having, the one thirty-six, the other about two hundred tentacles. The former of these, which I have honoured with the name of the late Edward Forbes,[129] differs much in general appearance from the little Sarsia, being a cake-shaped segment of a globe, about three or four inches in diameter, and an inch and a half in thickness. The roof of the interior is low and nearly flat, or indeed dropping slightly in the centre.

PLATE 29.

P. H. GOSSE, _del._ LEIGHTON, BROS.

FORBESIAN ÆQUOREA.
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