Part 4

The story of the growth and development of these little jellies is one of the most marvelous pages in the history of nature. In some forms the father and son are entirely different, and it is only the father and grandson that resemble each other. Not only this, the father is a seeming plant, while the son is a free-swimming jellyfish of great beauty. The seeming plant is in reality a hydroid community. The buds are immature jellyfishes which finally break away and assume the typical jellylike form, free swimmers bearing not the slightest resemblance to the parent. This jelly deposits eggs which attach themselves to the bottom and become not jellies but the shrublike form. Hence it is the parent and its grandchildren that bear a close resemblance to one another.

No conception of the beauties of the jellyfish can be formed from pictures, or from the stranded "sunfishes" found along the shore at low tide. In the water they move along or swim by the slow pumping or rising and falling of the umbrella or disk, and are of all the colors of the rainbow. Some, like the dark, lavender-splashed specimens, can be seen from a long distance, while others are almost invisible, in fact, are like glass or crystal, and interpose no obstacle to other forms beyond. The ocean is filled with them; their chaste shapes presenting one of the most beautiful spectacles to be observed in the ocean as they drift about. Some are merely great disks towing behind them enormous masses of pink fluted jelly, as in Figure 23; others are simple flowerlike forms (Fig. 24).

If these graceful forms are beautiful during the day, what shall we say of them at night, when they blaze and glow with marvelous phosphorescent lights of yellow, green, and gold. Gazing into the ocean these great jellies appear like comets moving through the clear atmosphere of the sea. The Cyanea is pale blue. One jelly, called Melicerta, emits a pale golden radiance, and Rhizostoma (Fig. 25) gives out a fixed steely blue light. It would be difficult to find one out of all this marvelous procession of living gems that does not emit a light more or less peculiarly its own.

If this phosphorescence is fascinating as we are drifting over the scene and the light givers are not alarmed, how much more dazzling is the display when the sea is beaten into foam. In a certain cave on the coast of Santa Catalina Island, California, the sea rushes in and, striking the rocks, rises like a wave of fire and bathes the entire interior with liquid light which slowly falls in gleaming rivulets to the sea.

But the most magnificent display is seen at Point Firmin Light during a storm. Here stands a lofty rock pillar which has breasted the sea for ages. At low tide, when a storm sea strikes the ledge, the spray rises to an altitude of three hundred feet, and spreading as it rises, fairly fills the air with a gigantic mass of silvery light, that on a dark night presents an appalling spectacle as it drops, changing its shape continually. On such nights the line of breakers changes into silvery flame, while the roar resembles a cannonade, fairly shaking the earth. In the breakers the jelly light givers are breaking up and adding fuel to the seeming flame. Some, as Pelagia, are luminous over their entire surface; in others, the light is confined to certain parts, which are either fixed or flashing lights. How vivid this light is may be imagined when it is said that a single jellyfish, Aurelia, when squeezed into a glass of milk, has produced a light by which a letter was read.

This peculiar phosphorescence is not their only interesting feature. Nearly all the jellies afford protection to fishes, crabs, and various small animals. As I drifted over the waters of the Gulf of Mexico almost every large jelly that I examined had one or more little fishes of the mackerel family up among its lobes or tentacles. As they always resembled the tentacles in tint or color, a delicate pink, they found protection amid the death-dealing darts. The most remarkable example of this strange companionship of dangerous jellies and delicate fishes is found in the Physalia, or Portuguese man-of-war (Fig. 26), one of the most beautiful of all the animals that make up the group to which the jellyfishes belong. Physalia is a bubble tinted with purple hues, four or five inches long--a fairy ship of pearly tints. On its upper portion is a sail which can be raised and lowered, while from the lower part depends a mass of beautiful blue or purple tentacles which sometimes are nearly one hundred feet in length. During the summer of 1902 I found them on the outer islands of the Texan coast in great numbers, stranded on the sands, while scores of others sailed on through the pass into the quiet waters of Aransas Bay. Among the islands of the Tortugas group I often saw them dotting the calm waters, the sunlight on their delicate tints presenting beautiful combinations of colors.

It may appear strange that one of the most resplendent of animals should be the most dangerous, yet such is the case. The attractive tentacles which drag behind the Physalia are deadly to almost every fish. I have found a hawkbill turtle weighing twenty pounds caught and benumbed by one; and fishes which touch the seeming worms roll over dead, as though stunned by an electric shock. In swimming around one of the keys of the reef I unwittingly passed over the train of one, and if I had been alone, I doubt if I could have reached the shore, so terrible was the burning pain. A year afterward my flesh had the appearance of having been tattooed in fanciful designs. Yet despite the deadly nature of this maze of traps and lures, a little fish lives up among them, and what is more remarkable, is the exact color of the tentacles, a rich blue. So exact is this resemblance that it is very difficult to see the little attendants, but if you lift the dainty man-of-war by its sail, they rush about greatly alarmed by their exposed condition. I have been told that the Physalia eats these attendant courtiers, but in hundreds of specimens which I examined I never saw the little fish in the toils. They swam about among the death-dealing tentacles with the greatest freedom. The secret of the poison lies in the lasso cells of the tentacles, as in the case of the jellyfish, but in this instance they are much more poisonous. Along the southern beaches, where the Physalia is common, their stranded hulks form after storms a windrow of mimic balloons which explode like torpedoes beneath the feet, as one strolls along the sands.

No branch of the animal kingdom contains more beautiful and radiant forms than that which includes the Portuguese man-of-war. They are the fairy crafts of the sea, graceful, seemingly formed of water in some instances, and nearly all so delicate that they usually drop to pieces when captured. I have kept all for a brief time in confinement, but few survived more than a few hours.

In a tank at Santa Catalina Island I had at one time, besides a Portuguese man-of-war, the delicate Velella, a raft of sheeny silver which floated on the surface, having a silvery sail (Fig. 27), beneath which hung short tentacles of a brilliant hue. More beautiful than these were the "swimming bells"--strings of beautiful pink and crystal bells attached to a central cord (Fig. 28). One of these, Praya, three or four feet long, was a veritable string of little pumps, each of which pumped water very rapidly, urging the entire animal along. Each little cup seemed carved in glass and colored by some artist, so perfect were the tints, so delicate was the design. Many of these forms could be seen in the ocean only by fitful glances, so delicate were they. Most beautiful of all these prisoners in the tank was one called Physophora, or by the Italian fishermen, Boguetti. It had a central stem like the glass of a thermometer, the bulb being uppermost and filled with a gas that was almost exact in its resemblance to mercury. When the bulb was full the animal floated at the surface. I have watched the animal force the gas down by repeated restrictions of the tube until it could descend beneath the surface with ease. On the sides of the central pillar were numbers of beautifully tinted pumps, the locomotive organs. Underneath was a mass of lacelike tentacles, richly tinted, purple and vermilion, so Physophora was one of the most gorgeous objects to be imagined. A unique feature of this animal was its rapid movements. When it so desired it dashed around the tank with great velocity, in strange contrast to the labored movements of other jellylike forms, or the utter and complete helplessness of Physalia, Velella, or Porpita. These latter were ships at the mercy of every breeze, the Physalia alone being able to anchor itself on a lea shore, but always beaten in by the heavy surf.

IV. THE SEA ANEMONES

In the last century many of the animals of the ocean were considered plants, and the sea anemones, which appear to open and shut like flowers, were described and painted in verse and prose as the flowers in the gardens of the sea. The sea anemone, common in almost every rocky pool, and found everywhere from the rocks bare at low tide to the greater depths, certainly has a very flowerlike appearance, some of them resembling a flower without a stem. Petals branch out on every side. Some are large, some small, and as though to carry out the idea the anemones are of all possible shapes and colors. Some are vivid red, others blue, some almost white, others spotted black and white, brown and barred. Almost every color is seen. Some are tall and slender, five or six inches high; others are flat. Some live in exposed places, as the luminous form attached to the shell of a hermit crab in Figure 29. Others bury themselves in the sand or hide beneath large jellyfishes, displaying the most remarkable tastes and fancies. Little wonder that the ancients believed that they were flowers. But touch one, and presto! it appears to draw within itself, and becomes a mere mound in place of the gorgeous creature which spread its splendors to the current.

The sea anemone is a highly organized animal several degrees above the jellyfishes in the scale of life, yet a very humble creature after all. They are tubular in shape, and are attached to the rocks by a sucking disk which clings so tightly that it is only with great difficulty they are forced off. Yet they have the power of moving, and slowly, very slowly, drag themselves along. Some move perhaps three or four inches a day; but this would be a long journey for many anemones, and the greatest number are fixed for life and live in crevices in the rocks. The only one I ever saw actually moving was traveling slowly across the glass of a tank. As it moved small pieces of the disk appeared to be torn off and left behind, each of which grew into a perfect sea anemone.

On the upper portion around the rim are the tentacles, armed with the same kind of ammunition (Fig. 30) found in the jellyfish, namely, lassos. In the center is the mouth.

We may imagine the anemone feeding, and we may easily see what occurs. The anemone displays its beautiful flowerlike face; it is spread out, waiting for prey. A shrimp comes swimming along, and innocently drops upon the beautiful flower. The moment it touches the attractive arms it is pierced by the lassos, and unless very vigorous is soon involved. The arms are thrown over it, the body shrinks, grows perceptibly smaller, the shrimp is pressed against the mouth, and finally ingulfed, and the once gorgeous anemone resembles (Fig. 31) a mere mound, a form which it may retain until the food is digested.

The structure of this interesting animal may be observed by glancing at Figure 32. The stomach is placed in the center of the animal, and is held in position by a number of partitions that are attached to the side of the anemone. These form little rooms in the body of the anemone, arranged about the stomach, but not opening into it. Each room has two windows leading into the room beyond, hence all are connected, and at the bottom all are connected with the stomach. Each room connects upward with a tentacle, which is hollow. When the animal is swallowing, the food passes down and is floated in water through the various rooms, the hard portions being rejected at the mouth. The animal has a current of water circulating through it almost continually, and it is water which, filling them, makes the tentacles stand upright and firm. Between the bases of the tentacles are the eyes. When the animal closes up, it forces the water out of its mouth and is able to shrink to a small and inconspicuous object.

Lowly as are the sea anemones, they often display an amount of intelligence that few would give them credit for. On the Florida Reef was a large lagoon, its bottom pure sand, and so light that the slightest dark object was easily observed. In the sand, buried several inches deep, lived a large anemone, whose normal hue was a dark brown, but when expanded was almost the exact color of the sand; not only this, its tentacles were covered with bits of sand. In a word, the anemone had disguised itself so that large and threatening fishes would not see it, as they swam along in search of food. The habit of placing bits of shells and sand on the tentacles is a common one. I have noticed it in a sand-living form on the California coast. As the tide went out and left the anemones dry, they were invariably covered with sand which adhered to the tentacles as though it had been gummed. To accomplish this protection from the hot rays of the sun, the anemone had picked up the atoms of sand with its tentacles and distributed them over its surface. As there were thousands of pieces, the amount of work may be imagined.

Anemones are found in many strange places. One, as we have seen, rides about upon the back of a hermit crab; another is so often found on the top of an ordinary crab that it is evidently a habit of the anemone. The anemone thus travels about with its host and shares its food. In the Indian Ocean a German naturalist found on every crab of a certain kind, which he caught, a sea anemone fastened upon the inside of the large biting claw. Thinking it accidental, he caught a number of crabs, but nearly all had the small anemone, which was so placed that when the crab raised its claw to its mouth to eat and tear its food, the sea anemone was in a position to obtain a full share of the food. Still thinking that this must be an accident, the naturalist placed a large number of the crabs bearing the sea anemones in a tank and removed the anemones with a knife, placing them in the water. The following day when they were examined every crab had its attendant again upon its claw. Again the experiment was tried, and again the crabs collected their curious attendants. The naturalist now cut one of the animals into several pieces, and even then the crabs attempted to collect them.

The anemones deposit eggs in vast numbers, which change into strange, free-swimming animals that finally settle upon the bottom and soon grow into the adult forms. They have another method of developing. Singular little "buds" appear on the sides and base of the adult, which soon resemble the parent. The anemone is very long-lived; specimens have been kept for nearly a century. They also have a marvelous faculty for renewing themselves if injured. If one is divided, sometimes two anemones will be the result, recalling their distant cousin the little hydra, which when turned inside out receives its food and eats as though nothing had happened. No amount of mutilating appears to affect its various portions, as each soon develops into a perfect hydra.

The sea anemone is a common form of the aquarium. It is easily secured by those living near the ocean, forming a most interesting pet, taking food from the hand, and soon proving itself possessed of a remarkable appetite. The anemones are among the great purifiers of the ocean, devouring a vast amount of dead matter which might pollute the water, and continually pumping the water through their systems, sifting out the animal life, dead or alive. Aside from this, the anemones are chiefly useful as beautifiers of the ocean. In the Mediterranean Sea they are sometimes eaten by the Italians and French. Certain fishes and crustaceans prey upon them.

V. THE CORALS

The real gardens of the sea, the "Gulfs enchanted where the siren sings and coral reefs lie bare," are in the tropics, where the great coral reefs extend for miles in countless shapes, forming branches, heads, fans, and many forms which never fail to delight the eye of the observer. For many years I lived upon a coral key or island in the center of a coral reef. The key was half a mile in circuit, and was made up of coral sand, or sand composed of ground coral and shells. It was just above the surface, so near that almost anywhere salt water could be found a few feet below; yet in this sandy soil cocoanuts, bananas, and other tropical plants grew in profusion. A grove of bay cedars and mangroves added to its attractiveness and gave it the name of Garden Key.

The history of this reef is easily told. Ages ago there was no reef. There was no island, but perhaps a submarine plateau, a long distance below the surface. It gradually grew by the dropping of the minute shells described on page 15. After many ages it attained an altitude which brought its summit within one hundred or two hundred feet of the surface. Now its growth became more rapid as a new factor came upon the scene. The reef-building corals do not, as a rule, thrive or grow in water deeper than two hundred feet, and nearly all prefer water very much shallower. So, as soon as the submarine hill entered this zone, the eggs and young of the various reef-building corals (Figs. 33, 37) obtained a foothold, and the growth was ever upward, countless forms aiding in it. The lower portion was continually dying, the animals occupying only the upper story, so that a cap of stone was being formed on the top of the hill which after many years reached the surface. The sea now broke up the tips of the branch coral. They became ground up. A curious seaweed which secreted lime appeared, and this and the ground coral and shells formed a muddy flat which, aided by various objects that float upon the ocean, constituted a miniature island. Now something which resembled a cigar, one end downward, came floating along. If we could have examined it, curious little rootlets would have been seen growing from the lower portion. This stranded on the island, and the little cigar proved to be the seed of the mangrove tree; its roots grew and caught in the mud, and soon a tree appeared growing on the new-born island. Its roots presented a base, about which sand and mud rapidly accumulated, and so the key or island grew until it became the Garden Key of to-day.

Such is the history of an ordinary coral island, built up, not by corals alone, but by countless animals. Even to-day some writers describe this coral animal as an "insect," but it is an entirely different animal, being a polyp, so closely related to the anemones that very few can distinguish between them. For the purpose of examination we may consider a coral animal as a sea anemone possessing the faculty of taking lime from the sea water and secreting it in the little rooms which we have found existing in the anemones (Fig. 32), there forming a little platform, then partitions or cells, as the case may be. In Figure 33 is shown a section of branch coral. The starlike spots are the polyps with their tentacles outspread as in feeding. They may be considered so many anemones, each resting in a little cell, and all connected by a common brown or olive-hued tissue. This is a many-celled coral, while that shown in Figure 34 is an example of a single-celled coral, a huge anemone with a framework of lime. These single-celled corals are often found in very deep water.

In the vicinity of Garden Key on the Florida Reef there are six or seven keys, each almost surrounded by a deep-blue channel. On the east a long fringing reef is forming which some day may form an atoll (Fig. 36). In this lagoon are acres of beautiful branch coral, rising two or three feet from the bottom in a mass of points almost bare at low tide, and at the very lowest tides becoming exposed and dying. At certain places on the edges of channels are vast heads of coral (Fig. 37), some being four feet high and six or seven feet across. Many of these are hollowed out into great vases and filled with beautiful sea fans, the Gorgonias, in yellow, lavender, and brown, while in and out swim fishes of beautiful colors. The surface of these heads is often dotted with objects which resemble flowers of gorgeous hues, red, blue, white, and spotted. At the slightest alarm or jar these disappear, showing themselves merely worms, which have bored into the coral, the flowerlike petals being the breathing organs. Along the sides of the channels the groves of branch coral (Fig. 33) dip down, and thirty feet below the surface the growth is much more vigorous, the branches often being three or even four feet in length, and resembling the antlers of the elk.

Wishing to see how deep the coral descended, I had a boat held on the edge of the channel, and taking a heavy stone in my hands allowed myself to sink. The stone carried me down rapidly for perhaps twenty feet, until the water was perceptibly colder and the light very dim, yet as far below me as I could see, the almost perpendicular wall of coral extended, being in all probability sixty feet in height and almost vertical. As I swam upward not four feet from the jagged points, I could plainly see the beautiful coral with parrot fishes garbed in brilliant tints, poising among the great branches.

The coral on this reef grows or flourishes more or less in communities. The great heads are found in groups, the branch coral in plantations, if the word can be used, in the center of the lagoon and on the edge of the deep channels. On a shallow point, growing among seaweeds, I found small heads five or six inches long.

In the surf, where it piled in upon the reef, grew a beautiful form known as leaf coral, spreading out like the horns of the moose in great leaflike shapes. This crept near the ground, and was surrounded by its cousins, the Gorgonias, in lavender and yellow. The whole presented a beautiful appearance when seen from above through a water glass or glass-bottomed boat.

In most of these corals the branches were covered with the small cells of the coral animal, made up of thousands of individual polyps. Others again had very minute cells, yet the entire head might weigh a thousand pounds. Another large head is called brain coral, as the animals are arranged in deep trenches or convolutions. In the star coral (Astræa, Fig. 37) the polyps resemble stars and are much larger than those on other corals.