The mighty deep

“WE have already learned,” wrote Albert, Prince of Monaco, not long since, in reference to recent Ocean researches—“that a whole world of Fishes, Molluscs, Annelids, Medusæ, Cephalopoda, and Crustaceans, come to the surface at night, and return before day to a depth of some hundreds of fathoms, forming a living tide which ebbs and flows in every sea.”

Letting alone for the moment other creatures mentioned in the above list, let us think about the vast world of Medusæ—of Jelly-fishes and their relatives—with which the Ocean is largely peopled.

Whether Hydroids, Jelly-fishes proper, Coral-polyps, or Sea-Anemones, they all belong to a low order in the Animal Kingdom. Higher, certainly, than the minute specks of life described in past chapters; higher than Foraminifers; higher than Sponges; but lower than Sea-urchins and Starfishes; very much lower than Worms and Oysters.

They vary immensely in size, ranging from minute jelly-bags, without limbs or heads, mouths or stomachs, to great masses of jelly-like substance, with eyes and mouths and powerful stinging apparatus.

All these are included in the circle of near relatives to the “Medusæ,” which name was first bestowed upon the anemones from a supposed likeness between the snaky tresses of the mythological Medusa and the tentacles of these soft-bodied animals.

“Ocean-flowers,” many of them may truly be called, since they live and grow, rooted like a plant to one spot; since also they put forth veritable buds and blossoms. Only they are in nature not vegetable, but animal. Many of these ocean blooms are exquisitely beautiful; but they may not always be gathered with impunity.

“Ocean-lamps,” too, many may with truth be named. Large numbers of the coral-polyps, large numbers of the hydroids, and perhaps all of the free-swimming medusæ or jelly-fishes, carry with them their own little lanterns, wherewith at night to make bright the surface of the sea—wherewith also to bear glimmers of light downward into those black depths where sunlight cannot reach.

That Jelly-fish which “swam in a tropical sea,” and said, “This world it consists of ME!” must have been an unusually intelligent specimen of its kind. Jelly-fishes in general are not credited with even much bodily sensation, far less with mental originality.

Coral-polyps have had their meed of attention in an earlier chapter. There is a near relationship between the reef-builders of equatorial seas and the anemones of British sea-beaches. But the anemone is a creature of distinctly higher development than the co-operative coral-polyp. It has at least the great gift of individuality, which its reef-cousins have not.

Sea-anemones have been compared to garden asters, and indeed the resemblance is not slight. The living tentacles of the one might almost be taken for a rough copy of the thick petals of the other.

In general form sea-anemones are round soft disc-like bodies, surrounded or trimmed by a border of fleshy tentacles, and mounted on a thick fleshy stalk or cylinder, which is usually either fastened to a rock or buried in the sand.

They vary in size between half-an-inch and more than a foot in diameter. A splendid specimen, to be found in the Pacific, is fourteen inches across the disc.

These creatures are not without a limited power of moving from place to place; though, in the case of most “attached” anemones, movement is extremely slow. A few kinds do not attach themselves at all, but rove freely through ocean-waters, after the fashion of their cousins the jelly-fishes.

One particular species, which seems to approve of change of scene, and yet not to love exertion, has hit upon a clever dodge.

When quite young it fixes itself upon the shell of a certain kind of crab; and as it grows larger, it gradually covers the whole back of the crab. Where the crab goes, the anemone goes; when the crab rests, the anemone rests. Oddly enough, the crab does not appear to object to his burden.

This is no mere accidental comradeship, seen only in rare cases; for that special description of crab is never seen without its friend the anemone perched confidingly upon its back; and that special description of anemone is never seen without its friend the crab for a steed.

A sea-anemone, like a coral-polyp, has a mouth and a stomach. But unlike the coral-polyp, it has the mouth and stomach for its own use, not merely in trust for the benefit of the whole community.

When the pretty flower-like creature wishes to open itself out, it takes in a quantity of salt water. When it wishes to shut itself up, it spurts the water out, drawing its tentacles close.

Both mouth and stomach are elastic; and it is able to swallow animals that are very little smaller than itself. Sometimes it gulps up greedily a whole crab or bivalve, digesting the soft animal parts, and getting rid of the useless shell as easily as it gets rid of water, when about to close.

Soft and mild and helpless as a sea-anemone may seem, it is really far from being defenceless.

Within that plump body, around the mouth, in the skin, about the tentacles, and along the slender hanging white cords, lie concealed thousands, even millions, of weapons. Each weapon is a very fine and delicate thread of hollow make, curled tightly up in a minute cell, ready for use. When a sea-anemone desires to injure or to kill, either in defence or in attack, it darts out a number of these little “lassos” as they are called.

Each lasso is not merely unwound, but is actually turned inside out, as you may turn a stocking inside out, when drawing it off. And as the instantaneous process takes place, poison flows with the tiny dart into the wound that is made. Small though each lasso may be, when dozens or hundreds of them are launched together, the result is not contemptible, even as regards man; and ocean creatures die fast from the poison.

A cell which contains a lasso is about one five-thousandth of an inch across; and two hundred lassos, placed end to end, would reach to about an inch in length. When once a lasso has been darted forth, it can never again be used, because it cannot be returned to the cell. But so great are the supplies of them, that a sea-anemone never gets to the end of its armoury. Even if all were used, others would speedily grow in their place.

Some kinds of animals, living in the sea and of service to man, are in danger of being thinned out of existence by the incessant ravages of net and trawl, of hook and harpoon. Not so the world of Anemones. So vast are their numbers, so rapid is their increase, that no antagonistic forces can annihilate them.

It has been said that if every anemone on British shores were one day swept away, carried off by an army of ardent naturalists, or destroyed by waves in some tremendous tempest, the next inflowing tide would bring a fresh supply, sufficient to fill all gaps.

Not less numerous, perhaps far more numerous, are the countless hordes of Jelly-fishes, so called, though they are not fishes—of Sea-nettles, so called, though they are not nettles.

They travel freely through the ocean depths, like fishes; and they sting sharply, like nettles. Yet they are neither.

Another name given to them is that of “Sun-fishes,” because in calm weather they often float close to the surface of the sea, as if delighting to bask in sunshine. One could almost imagine that, after the fashion of modern “luminous paint,” they are taking in sunlight, to carry stores thereof later into dark depths, for the benefit of less favoured comrades. But let a heavy storm arise, and swiftly these fragile creatures wend their way into the placid depths, beyond reach of wind and wave.

Many years ago a story was told of a certain farmer, who had heard that medusæ were particularly good as manure. He had large supplies of them carted to his land, with much expense and trouble. Not till later did he learn how small a part of the creatures consisted of anything but water; how easily he might have had the whole mass of them dried, and then carried by hand, at almost no cost.

Medusæ, as earlier stated, are of all sizes, from tiny translucent bags of liquid to huge discs of jelly-like substance, rivalling a man’s umbrella in diameter.

They are also of all kinds and shapes. Many of umbrella-shape have, in place of a handle, bundles of fleshy tentacles hanging down below, and thin streamers reaching to a length of a hundred feet. Some are more like saucers or bowls. Others of longer and narrower make have been likened to large thimbles. Some are ribbon-like beings, moving in graceful serpentine folds. Others have the outlines of elegant tubes. Many, again, are like little inverted delicate shrubs, or fairy-seaweed fronds, hanging downward. Some carry sail upon the surface of the water.

While all are of a more or less jelly-like substance, some are so frail and watery that they can only be lifted out of the sea in a pail. Any other mode causes them to drop to pieces.

But the most wonderful and beautiful characteristic of the jelly-fish is that of its self-illuminating power.

Here is a description of one kind, found in the Atlantic, near the coast of North America:—

“Objects of more exquisite beauty than some of these hydroid-medusæ do not perhaps exist. Each minute crystal chalice, with its beautifully curved outline, elongated delicate tentacles, gently coiling and uncoiling, and its slender proboscis which hangs like a lamp in the centre, lighting it with a soft phosphorescent glow, is the very type of delicate beauty, suggesting the wonders of fairyland.”[4]

And here is another description, no less striking; not this time of a floating medusa, but of a small coral-zoophyte, about ten inches long, common in the Mediterranean and in the Atlantic:—

“Nothing can exceed the beauty of the elegant opaline polyps of this zoophyte when fully expanded, and clustered like flowers on their orange-coloured stalk; a beauty, however, almost equalled by night when, on the slightest irritation, the whole colony glows from one extremity to the other with undulating waves of pale green phosphoric light. A large bucketful of these Alcyonaria was experimentally stirred up one evening, and the luminosity evolved produced a spectacle too brilliant for words to describe. The supporting stem appeared always to be the chief seat of these phosphorescent properties, and from thence the scintillations travelled onward to the bodies of the polyps themselves.”[5]

Travellers in all ages have described the marvellous illuminations seen at night on the ocean surface; illuminations long a mystery to those who gazed with admiration. At times the whole sea is one blaze of light; and the ship cleaves her way through liquid silver, or crimson glory, through milky whiteness or flames of blue and red.

And the greater part, if not the whole, as we now know, is due to uncountable multitudes of jelly-creatures, floating close to the surface, each contributing its tiny share to the radiant sheen. Sometimes they are large enough to be visible to the naked eye, but more generally they are minute microscopic beings, far too small individually to be seen by us, yet apparent in the mass by their united brilliance.

If millions of their glowing lamps shine in ocean’s deeper parts, we need no longer marvel to find deep-sea animals with large and well-developed eyes.

While on this subject, it should be added that the Medusæ have not a monopoly of ocean-lamps. Other creatures share in the task of lighting up those midnight depths.

Not long since two new species of fishes were discovered off the Azores, both of which possessed delicate organs of light-giving power. In one of them the rows of tiny lamps could be used or hidden “at will”—allowed to shine upon the world around, or shut off by a thick dark skin, somewhat after the fashion of a policeman’s “dark lantern.” Cuttlefishes too have been found carrying natural lamps for sub-ocean use.