Part 28

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.

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:

Solaster papposa, represented, about one-third of the natural size, by the right-hand figure on Plate XXV.

Ophiocoma granulata, seen in the upper left-hand corner of Plate XXV.

Gonoplax angulatus, the principal figure in Plate XXVI., occupying the foreground.

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.

E. Pennantii.

Aquarium (2d Ed.), p. 154.

Pagurus Bernhardus; so called, I presume, from Bernard, the monk, in allusion to its passing its life in its cell: whence also “Hermit-crab.”

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.

See my Aquarium, p. 156, et seq.

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.

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. 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.”