Part 5

Occasionally I have found a branch of coral on which there was, perhaps, a bunch of eight cells, each half an inch across, the group resembling a bunch of flowers. These were generally in the deeper parts of the lagoon, where the water was fifteen or more feet deep, and therefore out of reach of the coral tongs. I would, therefore, dive down for it, the coral being distinctly visible in these clear and limpid waters. This rose coral, as we called it, was the work of a few polyps. Another kind was very delicate, the polyps being almost invisible. It was called pepper coral, as when tasted it burned the tongue violently. Still another, which grew in heads a foot or two across, had a peculiar habit of floating when free of animal matter. Large heads, when tossed from the beach where they had drifted, went sailing away like boats.

Still another coral has cells at short intervals up the branch; another is cup-shaped with a single polyp. One of the most remarkable corals (Fig. 38) has the cells of the polyps arranged after the fashion of a pipe organ, from which the coral takes its name, while the polyp itself, when expanded, resembles a daisy. Formerly corals were supposed to be confined to the warm waters of the tropics, but this is true only of the reef builders, which require a temperature not lower than 63°, and are rarely, if ever, found at a greater depth than about 180 feet. Single polyp corals, like Fungia, are found at great depths in the ocean, and certain corals grow in the Santa Catalina Channel on the Pacific coast. In the Atlantic, as far north as Long Island Sound, where the water is often icy cold, is found the beautiful Astrangia, a coral in which the polyps are pure white and about five one-hundredths of an inch in length.

In a general way we have passed in review some of the typical corals, and may now glance at their manner of growth. If we cut one of the cells of a coral across, we shall have a figure similar to that shown in Figure 39. The white radiating partitions are coral, the black spaces are rooms, which correspond to the little apartments in the anemone. The coral develops by eggs and by budding, just as in the case of its cousin, the anemone. The eggs, after enjoying a free-swimming life for a while, settle upon the bottom and begin to secrete lime. They do not build up a house as the mythical "coral insect" is described as doing, but secrete it much as any animal secretes its bones or shell. As the water flows through the animal it is enabled to secrete the lime dissolved in the water. If we could watch every step of the growing process, we should first see a little platform of lime attached to the stone or object upon which the young coral animal has dropped, then a little edge or rim which increases in size daily. Out from this rim shoot the partitions, as shown in Figure 39. It will be observed that they do not meet and join, but leave a place in the center for the stomach. Finally, the cell is completely formed, and we have a perfect cup of lime, a coral cell in which is ensconced the anemonelike coral polyp. Its color is an olive brown, and when the polyp is expanded its little tentacles resemble the petals of a flower. With these it catches food, which it eats in very much the same way as do the anemones. If this cup is a branch coral, soon a bud appears upon the side, and a new cup or cell takes shape. Then another is added, and we see the coral enlarging, branching out either by budding or simply dividing until a large branch is the result.

This growth is much more rapid than is generally supposed. The brain coral has been known to grow an inch or double its size in a year, and branch corals grow six or eight inches in this time. The corals and reefs form the great girders of the globe. The one off Australia is over a thousand miles in length, and all over the world are found fossil reefs. Thus in the Helderberg Mountains of New York I have followed and traced a coral reef, quite as wonderful in its way as that now growing and reaching out in Florida. By some upheaving of the earth's surface it has been pushed up into the air, a monument telling of the wonderful changes in nature and of the time when the waters of New York were as warm as those of Florida.

Side by side with the corals and among the most beautiful objects of these submarine gardens, we find objects which resemble plumes and fans (Fig. 41). These are called Gorgonias, and are cousins of the corals. They resemble fans made up of a fine network or reticulated surface (Fig. 40). They are richly colored yellow, brown, and lavender, those of the latter color being particularly beautiful. When there is a surf they can be seen waving and bending gracefully, like the limbs of a tree in a gale. One of the best known of this group is the red coral of commerce, found in the Mediterranean Sea and the Indian Ocean. When alive, the coral base or branch is covered with a crust or skin in which the animals live, connected one with another. The polyp stands very high and is white. The crust itself, the solid lime base, is formed of a number of minute parallel tubes. This coral is dredged by collectors in the deep water and is scraped and polished until the beautiful red color, so highly prized for jewelry, is brought out.

Closely allied to the corals are the sea pens (Fig. 42) which are common in almost all waters, and among the most beautiful forms. They are communities of polyps. In the sea pen the polyps are arranged along the branches so that a fluffy fan or an ostrich plume is imitated. I have taken these animals from deep water when they measured perhaps five inches in length; but an hour later when placed in a tank the insignificant animal had expanded until it was five times as large, and beautiful beyond description in its garb of delicate pink. At night it was a blaze of light which flashed from branch to branch, from polyp to polyp. When irritated in a perfectly dark room this specimen created so brilliant a phosphorescent light that I could almost read large print by it.

In the deep sea lives a giant form, the Umbellularia, four or five feet high; and there are many more, all of which add to the lights of the deep sea. Near allies of these attractive forms are the comb bearers, free-swimming, jellylike forms of great beauty and grace. I have kept the radiant Pleurobrachia in a tank where I observed its wonders and beauties. The one known as Veretillum (Fig. 43) is very beautiful and a marvelous light giver.

VI. THE STONE LILIES

A number of years ago I took a number of walking trips over that section of New York state known as the Catskill Mountain region. The start was made at the mouth of Catskill Creek, which was followed up into the mountains until we came to a peculiar light, slate-colored rock. This rock, where the stream had washed the earth away, was dotted with little disks (Fig. 44), which being harder than the rock itself had been weathering, and stood out in high relief. A mile or two from the river the rocks were covered with these disks, in fact, seemed to be made up of them. Some were large, some small, as if millions of pipestems had been cut into sections and scattered about.

These disks told an interesting story. We read by them that ages ago the region now covered by farms and summer resorts was the bottom of a shallow, tropical sea. We could go further and describe even the appearance of the bottom of that sea, and what grew and lived there. Scattered about on the rock were myriads of shells, corals, teeth, fish bones, and a variety of objects, all the remains of animals which once lived in this ancient ocean.

We find that the little disks fit together, and collecting them, pile them up, forming a stem a foot or more long. Among them we find one which is attached to a rootlike object, and this is placed at the bottom. Near by we find a flowerlike or budlike form (Fig 45), which may well serve as the flower of this stem, and so we add it and produce a striking resemblance to the crinoid shown in Figure 46. This is an interesting and beautiful animal which was one of the commonest forms of the ancient seas. It grew in groves and masses, as we may see by the vast numbers strewn in the old ocean bed; and when they died, they were scattered here and there and hardened into the old bed.

The crinoids resemble lilies so closely that they are called stone lilies. They are animals, however, related to the starfishes. They have a long stem, with rootlike branches to support it, and are capped with what appears like an inverted starfish, and is literally a starfish perched upon a stem. Fossil crinoids have long been known, and beautiful specimens may be seen in all our museums, but the fact that they still live upon the globe is a modern discovery. It is said that Agassiz stated that he expected to find them alive off the coast of Cuba, and when a deep locality was dredged, up came the living crinoids, or forms almost identical with them. Since then they have been dredged in great numbers by all the great deep-sea explorers. Some have long stems, some short. On one, the Comatula, when it is full grown, the crinoid leaves its stalk, and lives a free, roving life after the fashion of many starfishes.

The crinoid, with its long slender stem, its branching tendrils, its flowerlike top, is one of the most graceful of all animals, as might be imagined from the drawing. Examine the crinoid as closely as one may, it still resembles a stone lily, and only its slow movements, contracting and folding, suggest life. Nevertheless, it is a very complicated animal. It consists of a central body, protected by numerous plates, as seen in Figure 46. From the edges extend five, or often more, branches or arms, and from them in turn branch other arms, so that the top resembles a feather or brush, from which they are called feather stars. In the center of the stars is a mouth, food being caught by the many branching tentacles. The history of the development of crinoids is very interesting. They pass through several curious stages in the course of growth from infancy to old age, and some of the shapes are so curious that no one, not familiar with them, would suspect that here was a growing crinoid.

VII. THE STARS OF THE SEA

Beneath almost every rock along the New England coast, and under the branch coral in the tropics, we may find a typical star-shaped animal, and by dredging offshore, thousands are brought up, even from very deep water, showing that the stars of the sea are almost as plentiful as they appear in the sky above. These starfishes are of all shapes, kinds, and colors. Some are a foot or more across, huge, domed fellows with rough backs, showing little if any signs of life (Fig. 48); others have five long legs and a small body (Fig. 49). Others, again, are perfectly round and have many rays, while some have few rays which are round, like the body of a snake, and which they whip and slash about, displaying great activity. Once in reaching beneath a coral branch to find a certain shell which I knew lived there, my hand grasped something which felt like a ball of snakes, each of which closed about it, producing a most disagreeable sensation. I drew it out and found it was one of the starfishes, common on many shores as the basket starfish (Fig. 47). As I lifted it up it was a veritable mass of coiling arms, a Medusa's head of the sea, coiling and uncoiling. It was merely a starfish in which each arm branches in two parts, each branching out into two again with the result pictured, a confused mass of arms. As I lifted my capture above water and it felt the air it began to shed its arms, so that it fairly rained pieces of starfish, and before I reached the boat, but a few feet away, all that remained was the body. My starfish had almost committed suicide.

The starfishes are found everywhere in the tropics. Every bunch of coral contains scores of them. Many resemble spiders, and are a vivid red hue, others are bronze or brick red, while still others are barred or spotted, as in Figure 50. They are all interesting creatures, especially our common Eastern starfish, which is found in little caves at low tide, clinging to the walls. It is not very attractive in appearance, and apparently not disconcerted by being left by the tide.

If we take a common starfish and turn it upon its back, we observe that the lower portion is covered with short tentacles, each having a little sucker on the end. These are the feet of the starfish, by which it walks or moves. In the center of the body is the mouth leading into the stomach which reaches into each ray. The eyes are at the tip of each ray. On the back of the star we find a little red disk with a rough surface. This is really a sieve for straining the water which pours in through a little canal encircling the mouth and leading off into each arm, carrying water to each one of the myriads of feet.

The feet move independently, and the starfish walks much faster than would be imagined. This can be illustrated by the sudden appearance of the starfish, in Long Island Sound. One night when the oyster men left the beds no starfishes were seen. The following day they were there in such vast quantities that it was estimated they covered the entire bed, two or three deep, and tens of thousands of dollars were lost by the destruction of the oysters.

How an oyster can be opened by a soft, helpless starfish would seem a mystery; but it is a very easy matter. The starfish drags itself over the shell and places its mouth at the end, extending its long arms downward, literally swallowing part of the shell. It is supposed to eject some secretion into the shell that causes it to open.

VIII. OCEAN HEDGEHOGS

(The Echini)

On the Florida Reef and off the rocky shores of California one of the most conspicuous among the rock-living animals is the black, long-spined Echinus. In the water it looks like a huge pincushion (Fig. 51) filled with black pins, points outward, and every crack and crevice is filled with them. When found on the beach, despoiled of their spines, they resemble bleached shells, and are then known in Florida as sea eggs (Fig. 52). The long black spines are continually moving up and down, and constitute the armament of the sea urchin, and an effective one to all except very large fishes, as some rays, which have pavementlike teeth fitted particularly for such not especially dainty morsels. The spines emit a bluish secretion which is left in the wounds made by them, and is more or less poisonous. This common sea urchin is a type of hundreds found in almost all seas from very shallow water to the abysmal regions of the ocean.

Some sea urchins have short spines (Fig. 53) and are almost pure white; some are flat like the sand dollars, the spines feeling like sandpaper, so short and fine are they. The latter are small, and appear to be covered with waving filaments. Many have spines like needles; in others the latter are blunt, clublike organs. Many other strange variations are seen in an exhibition of the various kinds in some museums. None are more remarkable than those having five holes through them like Chinese money (Fig. 54).

The urchins are very closely allied to the starfishes, especially in structure. They have the same kind of feet, and among the spines is seen a singular handlike organ common to the starfishes. It has three fingers (Fig. 55) and a short stem, and is constantly in motion, its office appearing to be to clean the body. Foreign objects are taken up by this peculiar hand and passed on from one to the other until they are finally dropped off. Here is the same madreporic plate or sieve, and the structure of the Echinus (Fig. 56) is very similar to that of the starfish. The former has a long set of jaws, hence is a biter and nipper, while the starfish is a sucker. The shell of the Echinus is really a beautiful object when divested of the spines and bleached in the sun, appearing as pure white as coral after bleaching. It is made up of about six hundred hard, limy plates arranged in double rows, which contain about thirty-seven hundred pores through which the feet protrude. Despite this marvelous supply of feet, or organs of locomotion, the Echinus is a very slow walker. The spines number four thousand or more, and each one works on the ball-and-socket plan, is hollow, and moves readily in all directions.

The sea urchin is produced from eggs. The young pass through some remarkable changes before they assume the adult form. In one of these changes they appear as free-swimming animals (Fig. 57), and resemble anything but the perfectly developed Echinus. Some of the sea urchins of deep water, as the Hermiaster and others, carry their young in pouches, the spines being folded over them to hold them in place. They rarely move from the crevice on the rock which they select. They can be found in the same place for months together, and have a limited power of wearing out the rock. How the Echinus grows inclosed in so hard a shell might be a puzzle did we not know that the shell is covered with a skin, each plate being literally surrounded by it. This skin secretes lime, taking it from the water and depositing it on the edges of all the plates, so that the animal grows rapidly and symmetrically. The Echini are the scavengers of the ocean, and they aid in maintaining the clearness and purity of the water. In some countries certain kinds are eaten, and one species is valuable for its spines, which are used as slate pencils.

IX. THE SEA CUCUMBERS

Once, when poling my boat over the great coral reef of the outer Florida Keys I came upon a little plot of seaweed in shallow water which was so covered with huge sea cucumbers (Fig. 58) that it would have been an easy matter to fill the boat. They were from six to twelve inches in length, two or three inches across, and bore a striking resemblance to actual cucumbers. In color they were brown, and when lifted from the water they slowly moved or twisted, sending out a stream of water. They might have been made of leather, so far as any evidence of life was concerned, and were so tough that a spear thrust into one had to be cut away, so tenacious was the hide of this singular sluglike animal. Taking a large one from the bottom, I placed it in a glass jar standing on the deck of my boat, whereupon a very singular occurrence took place. When the air began to be exhausted in the water of the glass, out from the sea cucumber came a long, slender fish, so ghostly and ethereal that when it died, as it did almost immediately, I placed it upon a piece of newspaper and read print through its body. The fish was known as Fierasfer, and it lived in the long intestine of the sea cucumber. Since then the fish has been closely studied in the Naples Aquarium, where it had the same habit, and where the attendant naturalists saw the fish come out, and return tail first.

The great sea cucumber of Florida may be taken as a type of all the group which differ mainly in size, color, and shape. Some are very short and have a decided flat lower surface; others are long, fragile, and easily broken; and many are brilliant in color. Nearly all are famous for their singular and often beautiful breathing organs which protrude from the mouth and bear the most remarkable resemblance to plants. In many specimens of the Atlantic Pentacta (Fig. 58), kept in an aquarium, this resemblance was very marked, as the animals at once buried themselves in the sand from which beautiful plants seemingly grew, being merely the breathing organs of the wily mimic. These organs vary much in size and beauty. In some species they are very elaborate, in others they are simple, flowerlike objects. The greatest variation is found in them. In one which I observed the tentacles resembled small toadstools.