The first instance of the octopus spawning in an aquarium in this country occurred at Brighton on the 19th of June, 1873. A large female octopus, caught at Dieppe, was brought in on the 26th of the preceding April, and, immediately on her arrival, a fine male previously received from Mevagissey conceived a liking for her, and evidently rejoicing in the good fortune which had provided for him a suitable mate, paid her such assiduous court, that his addresses were quickly accepted. It was a case of “love at first sight,” and in three days the captive damsel was wooed and won. The event above mentioned was, therefore, not unexpected. Our octopus, fortunately selected as a suitable site for her nest, a recess in the rock-work, close to the front glass of the tank, so that her movements could be easily observed. Her body just filled the entrance to it, and she further strengthened its defences by dragging to the mouth of her cavern two dozen or more of living oysters, and piling them one on another to form a breast-work or barricade, behind which she ensconced herself. Over this rampart she peered with her great, sleepless, prominent eyes; her two foremost arms extended beyond it, their extremities coiling and writhing in ceaseless motion, as if prepared to strike out right and left at any intruder. She seemed never to be taken unawares, and was no more to be caught napping than a cunning middy “caulking it” in the middle watch. Couchant, and on the “look-out,” like Sir Edwin Landseer’s lions, she barred with her body the passage to her den, ready to defend it against all foes. Her companions evidently felt that it was dangerous toapproach an excited mother guarding her offspring, and none ventured to go within arm’s length of her. Even her forlorn husband was made to keep his distance. If he dared to approach with intent to whisper soft words of affection into his partner’s ear, or to look with paternal pride on the newly-born infants, the lady roused herself with menacing air, and slowly rose till her head over-topped the barrier; by an instantaneous expansion of the pigment vesicles of the skin, a dark flush of anger tinged the whole surface of the body; the two upper arms were uncoiled and stretched out to their utmost length towards the interloper; and the poor snubbed, hen-pecked father, finding his nose put out of joint by the precious baby, which belonged as much to himself as to its fussy mother, invariably shrank from their formidable contact, and sorrowfully and sullenly retreated, to muse, perhaps, on the brief duration of cephalopodal marital happiness. All his fellows in the tank knew that he was in bad humour, and took care to keep out of his way. As soon as they saw him coming towards them they gathered their arms close together in a straight line, and swam off rapidly, tail first, to the further side of the tank.
Cluster of eggsFig. 6. Eggs of the Octopus.(O. vulgaris)
Fig. 6. Eggs of the Octopus.(O. vulgaris)
The eggs of the octopus, when first laid, are small, oval, translucent granules, resembling little grains of rice, not quite an eighth of an inch long. They grow along and around a common stalk, to which every egg is separately attached, as grapes form part of a bunch. Each of the elongated bunches is affixed by a glutinous secretion to the surface of a rock or stone (never to seaweed, as has been erroneously stated), and hangs pendent by its stalk in a long white cluster, like a magnified catkin of the filbert, or, to use Aristotle’s simile, like the fruit of the white alder. The length and number of these bunches varies according to the age and condition of the parent. Those produced by a young octopus are seldom more than about three inches long, and from twelve to twenty in number; but a full-grown female will deposit from forty to fifty of such clusters, each aboutfive inches in length. I have counted the eggs of which these clusters are composed, and find that there are about a thousand in each: so that a large octopus produces in one laying, usually extended over three days, a progeny of from 40,000 to 50,000. Our brooding French octopus, when undisturbed, would pass one of her arms beneath the hanging bunches of her eggs, and dilating the membrane on each side of it into a boat-shaped hollow, would gather and receive them in it as in a trough or cradle, exhibiting in its general shape and outline a remarkable similarity to those of the argonaut, or “paper-nautilus,” with the eggs of which octopod its own are, as I have already explained, almost identical in form and appearance. Then she would caress and gently rub them, occasionally turning towards them the mouth of her flexible exhalent and locomotor-tube, like the nozzle of a fireman’s hose-pipe, so as to direct upon them a jet of the excurrent water. I believe that the object of the syringing process is to free the eggs from parasitic animalcules, and possibly to prevent the growth of conferva, which I have found rapidly overspread those removed from her attention. Week after week, she continued to attend to them with the most watchful and assiduous care, seldom leaving them for an instant except to take food, which, without a brief abandonment of her position, would be beyond her reach. Aristotle asserted that while the female is incubating she takes no food. This is incorrect.
In the tank with our specimen were seven others of her species, and to supply them with food about five-and-twenty living shore crabs (Carcinus mænas) were daily tossed into it. Although sheso seldom left her nest, she generally obtained her share of these, and would seize with her suckers, and draw towards her, sometimes, three at a time, one by each of three of her arms. Their shells were soon broken and torn apart by her powerful beak, and when she had devoured the contents the harddébriswas cast out of her den.
But although the old naturalist of Stageira was mistaken in supposing that the female octopus does not take food during the period of the development of her ova, he was right in believing that her anxiety for her progeny, and her unremitting care of them, tell injuriously upon her health. A brooding octopus shows signs of diminished bodily vigour, as a sitting hen bird loses flesh whilst hatching her eggs. Her respiration at times becomes laboured. When the water is inhaled (I use the word intentionally, for the animalbreathesthe oxygen contained in it) at the open part of the mantle-sac, the siphon-tube, at its orifice, is often drawn forcibly inward; and when the pair of bellows of the body close, the same opening of the tube is distended to its fullest capacity by the out-rush of the exhaled water. Repeated observations have shown that it not unfrequently happens that the vital powers of the octopus are so exhausted by her protracted maternal cares that she dies when relieved by the hatching of her eggs from the necessity of further vigils. Many also die in the act of spawning, or when distended with ova.
To return to our mother octopus at Brighton,—at the end of the fifth week from the deposit of her ova she began to exhibit considerable irritation and restlessness, in consequence of the annoyance she experienced from visitors trying to rouse her to movement, or to frighten her from her eggs, by knocking at the glass with coins or sticks, and flouting pocket-handkerchiefs in front of her. I found that on some of these occasions, in her excitement, whilst protecting her eggs from the supposed danger, she had torn away the lower portion of some of the clusters, and that their number was considerably diminished. It thereforebecame necessary to screen her from the public gaze. Fearing also that, notwithstanding the cessation of the interruption to which she had been subjected, she might by her over-fussiness destroy the remainder; or that even if her progeny were safely born, they might hatch out unperceived, and thus our hopes be frustrated and an important observation lost, I decided on removing some of them from the exhibition tank, and placing them in a smaller one in the laboratory, where they could be closely watched. The water was therefore run off till a depth of only about six inches remained; and one of the catkin-like bunches of eggs was carefully detached. To do this neatly, without disturbing the other clusters, was not so easy as it might be supposed; for not only did the hen octopus guard the entrance to her recess, and require careful handling, but the old male also was pugnacious. As soon as he espied his keeper in the tank, he strode forth from his corner towards him, looking exceedingly savage, and making a demonstration of attack which would have frightened a novice, and led a looker-on to believe that the intruder was about to be the centre figure in a Laocoon group of writhing, twining octopods, and to suffer the fate ofClubin, or to escape only after a terrible combat, likeGilliatt, in M. Victor Hugo’s novel. But the old fellow’s bark was worse than his bite, for on a bare arm being presented to him in the shallow water, he made no attempt to hold or bite it, but merely scrambled and crawled harmlessly over it.
By the removal of a portion of these eggs I hoped, also, that an interesting question concerning their development might be finally answered. Aristotle had been understood to affirm that the parent octopus “incubates” her eggs. I had always expressed very decidedly my opinion, derived from previous experiments on the eggs of the cuttle-fish and squid (SepiaandLoligo) that, the ova once impregnated, no incubation by the parent is required or takes place in a sense equivalent to that of a fowl developing a chick by the warmth of its body; but that her unremittingattention to them is solely for the purpose of protecting them from injury, keeping them free from animal and vegetable parasites, and preventing their being devoured by fishes, or members of her own tribe—possibly by their own father. If I had felt myself free to act according to my inclination, I should, at once, have removed a larger number of the eggs; but in matters concerning which nothing is positively known, and everything has to be learned, caution is requisite. There was good reason for hesitation, when care in the conduct of the observation might remove the doubts of centuries. The first thing to be ascertained was—Had the ova been properly fecundated—did they contain, each, a living embryo? The microscope answered “Yes.” Under a low power a young octopus was seen moving freely in the fluid contained in each transparent granule, the bright orange-brown colour in the pigment cells of its skin flashing, dying out, and re-appearing in another place, like sparks in tinder. And I was astonished to see that the little creature within the unbroken membrane was already endowed with the power of assimilating its colour to that of its surroundings. When light was reflected upon its surface, and through its translucent body, from a piece of white paper laid on the mirror of the instrument, it became pallid and colourless: on a bronze penny being substituted for the paper, it assumed a darker hue; and (which was still more remarkable) on its being disturbed by a slight compression or agitation of the egg, its surface became suffused with the red flush of anger and irritation which characterises the adult under provocation.
It having been seen that many of the eggs left in their original position had been bruised by the mother octopus, and that there were black marks on the stone beneath them, betokening the presence of decomposition, I was anxious to remove the remainder from her; but, for the reason above mentioned, amongst others, I considered it would be prudent to assure myself that the eggs transferred to the smaller tank retained theirvitality. Seeing, at the expiration of four days, that the young animals within them were as lively as ever, and progressing so rapidly that their escape from the egg might soon be expected, I had the larger tank partly emptied again, for the purpose of taking from the nest any that might still be uninjured. It was found, however, that those which had not been torn away by the parent had been squeezed by her between herself and the rock-work, and were consequently dead, only a very few showing signs of having been prematurely hatched by the violent rupture of the envelope. She had overlain her babies. Those which were taken from her on the forty-second day from their extrusion for special inspection, were successfully hatched, and I do not doubt that if they could have been kept clean and free from parasites this would have taken place if they had been detached immediately after they were laid. The young octopods made their appearance on the 8th, 9th, and 10th of August: the eggs had been extruded on the 19th, 20th, and 21st of June, and thus, although it was proved, as I expected, that the development of the embryo does not depend on incubation, the accuracy of Aristotle’s statement that its period in the egg is fifty days was completely and satisfactorily confirmed.
In the first week of January, 1875, another brood of young octopods was hatched in the Brighton Aquarium, and in this, as in the former instance, the period of development was that assigned to it by Aristotle. From observations made during the previous winter I did not expect that maturity would be completed within this term. Two “nestings” of octopus then occurred; and after twenty days, from time to time, as opportunity offered, when the mother left them for a minute in pursuit of an active crab scuffling away to the further end of the tank, one of the clusters of eggs was removed, and suspended in a separate cistern. The half-formed embryo was visible, though motionless, within the membranous envelope; therefore it was evident that the fertilisation of the ova had been effected. But although the parent, inboth cases, assiduously guarded them for nearly three months—almost twice the, apparently, normal period—they were addled, as were also those which had been detached from under her care. It appeared to me probable that the vitality of the embryo was destroyed in an early stage by the lower temperature of the water during the winter months, but I was not without hopes that their progress towards maturity might prove to be merely retarded by the same influence,—an effect which is well known to be produced by cold on the ova of the salmonidæ. In order to test this, some of the eggs were placed in a tank in the warm boiler-house, but without any beneficial results. Yet the brood referred to was hatched in water of the same temperature as that in which the former ones were addled, varying little from 54 deg. Fahrenheit. I am unable to account for this; so I reserve my opinion of the cause of failure, and am content to watch, and wait, and patiently note facts, and to abstain from propounding theories on unsafe bases.
Everyone who loves and studies animals knows that each differs from others of its species, in its habits and little ways, as distinctly as children, and men, and women are diverse in character and disposition. The horses you have owned, the dogs you have loved, your cats, parrots, and even your pet cage-birds and little white mice, have possessed widely varying characters and idiosyncrasies. Fishes, the crustacea, and even the octopods are not excepted from this individuality. The hen octopus in question, whilst on sentry duty guarding her undeveloped progeny, assumed a position and attitude totally different from that adopted by her predecessor in maternal joys. The syringing of her eggs with a current of water from the syphon tube was repeated by her; but she never cradled them, as did the other, in the expanded membrane of a limb. Her usual posture was with the under portion of her body presented to them, her eight arms turned completely back, exposing their under surface armed with their battery of suckers, the muzzles of the latter pointing in every direction, and the tip of the hard, horny beak, just discernible.The fine ends of the arms might sometimes be seen gently winding amongst the clusters of eggs as tenderly and lovingly as a father’s fingers through the tresses of a darling child, but there was no evident nursing in this case.
An octopus about to spawn, like some birds in search of a nesting-place, seeks the most retired nook she can find in which to deposit her eggs. The elasticity of her body enables her to squeeze herself through a very small orifice; and, therefore, the narrower the entry to her den the more suitable is it for her purpose, because the better adapted for defence against enemies and intruders. A curious instance of the choice of such a nesting-place came under my notice in March, 1874. Some fishermen, whilst dredging in the Channel off Brighton, brought up an earthen jar or carboy, which would hold about two gallons. It was covered with serpulæ, &c., and was forthwith taken to the Aquarium. There it was discovered that it contained an octopus and her eggs. The neck of the jar was only two inches in diameter: the octopus was a fully-grown specimen.
The young octopus fresh from the egg is of about the size of a large flea, and when irritated is of nearly the same colour. It is very different in appearance from an adult individual of the same species. At first sight it is more like asepia, without its tentacles, than an octopus. The arms, which will afterwards be four or five times the length of its body, are so rudimentary as to be even shorter in proportion than the pedal arms of the cuttle-fish, and appear only as little conical excrescences, having points of hair-like fineness, and arranged in the form of an eight-rayed coronet around the head.
At this early stage of its existence the young octopus seeks and enjoys the light which it will, later in life, carefully shun. It manifests no desire to hide itself in crevices and recesses, as the adult does, but swims freely about in the water, often close to the surface, propelling itself backward by a series of little jerks caused by each stroke of the force pump, which expels a jet ofwater from the out-flow pipe of the syphon. This contrast of its habits in youth and age is so remarkable that when, after witnessing the gay activity of the movements of the child-octopus, I again watched the furtive, skulking habits of its shrivelled-skinned father, I could not help comparing the latter with the old thief-trainer in “Oliver Twist,” and wondering whether there ever could have been a time in the life of Fagin the Jew when he was innocent and frolicsome, and played, and leaped, and ran, and danced, and revelled in the sin-exposing sunshine, ere the light of day became odious to him, and he shrank from it as a danger to be dreaded, and kept himself hidden in his den whilst his emissaries went out, like the arms of the old octopus, in search of prey for the benefit of their employer.
I can say but little concerning the fertilisation of the eggs of the octopidæ in a book intended for readers of all classes, but it is so remarkable that this chapter would be incomplete without a few words upon the subject. They are fecundated before, not after, their extrusion. In the breeding season a curious alteration takes place in one of the arms of the male octopus; according to Steenstrup, always the third on the right side, although it has been stated that the third arm on the left is sometimes the one thus affected. The limb becomes swollen, and from it is developed a long, worm-like process, furnished with two longitudinal rows of suckers, from the extremity of which extends a slender, elongated filament. When its owner offers his hand in marriage to a lady octopus she accepts it,and keeps it,and walks away with it, for this singular outgrowth is then detached from the arm of her suitor, and becomes a moving creature, having separate life,[18]and continuing to exist for some time after being transferred to her keeping. In the meanwhile the lost portion of the “hectocotylized” arm of the male is gradually reproduced, and in due time it assumes its former appearance.
The habits of the Eledone, of which there is only one British species,E. cirrosa, are the same as those ofOctopus vulgaris, from which it chiefly differs in having only one row of suckers instead of two along the under surface of its arms. Individuals of this species have occasionally deposited a few eggs in the Brighton Aquarium; but these have not, hitherto, arrived at maturity. They are considerably larger than those of the octopus, and not so numerous. The eledone is not so hardy as its relative, and, in captivity, the female generally dies in spawning.
It is impossible for any student or observer of these animals to avoid recognition of Aristotle’s wonderfully intimate knowledge of their life-history, embryology, sexual conditions, and anatomy. When I first saw the octopus guarding her eggs the thought immediately rose in my mind,—“Aristotle must have had an aquarium!” He might have learned by observations at the sea-side, on the coast of the Mediterranean, the mode of progress of the octopus when swimming and crawling, its change of colour when excited, the form of its eggs, &c., which he has correctly described; but it is impossible that he could have so exactly designated the duration of the existence of the embryo in the egg without having had opportunities of noticing the date of its extrusion, and that of the escape of the young octopods by the rupture of the envelope. His mention of the remarkable sexual development of one of the arms, its use in the impregnation of the ova, their apparent incubation by the mother, and her incessant attention to her charge, also indicates that, during the intervening time, the male and the brooding female were continually under his inspection. We are therefore led to the conclusion that the marine aquarium, in some form, is one of the things that are not “new under the sun.”