Homes Without Hands: Being a Description of the Habitations of Animals, Classed According to Their Principle of Construction

Before proceeding farther in the history of the Coral and its submarine home, we will see how it extends itself with such wonderful rapidity, and what is the process that enables fresh colonies to establish themselves, and existing colonies to spread themselves, both these operations being conducted on different principles.

How the Coral grows is a problem which was unsolved until a comparatively late period. Not only were naturalists ignorant of its development, but they did not even know in what kingdom to place it, whether vegetable or mineral. Opinions were long divided on this point, the men of greatest reputation inclining to the belief that it was mineral, while a very few thought that it must be vegetable, and that the flower-like rays of the polype were veritable submarine blossoms. But when a more careful observer announced that the Coral was really the production of an animal, both parties united in ridiculing his theory, and for a while the animal origin of Coral was put aside by the scientific world. Truth, however, prevailed, as it always will do, sooner or later, and every one nowadays knows that Coral is the production of animated beings.

Still, although the general fact is known, its details are not so familiar.

In the active season of Coral life, that is, from May to August or September, millions of young Corals are launched into the world. When they first pass into the sea from the mouth of their parent, they are tiny flask-shaped beings, covered with minute cilia, by means of which they can pass through the water with some rapidity. They have a kind of mouth at the small end, which corresponds to the neck of the flask, and it is a curious fact that they always swim with the large end forward.

After a time they change their shape, elongating until they look like little white worms, but still moving about after the same fashion. They pass some time in this phase of existence, and then settle down upon some fixed object, such as a rock, and adhere to it by the enlarged base. Scarcely have they done so than they again alter their shape, and assume a form so different that no one who was not acquainted with the little creatures could recognize them. Instead of being long and worm-like, they now contract themselves in length, while they proportionately increase in width, and look something like an echinus, or sea urchin.

It is a curious fact, that up to this time they have passed through four stages, and in each stage they change in length. Before they issue from the parent they are nearly spherical, but when they pass into the sea they assume the flask-like shape. They next elongate themselves considerably, and then suddenly become even shorter than their width.

In this fourth stage the mouth is surrounded by eight little cushion-like projections, which soon sprout into the beautiful fringed tentacles which give to the animal so flower-like an appearance.

When it has arrived at this stage of existence, the young Coral begins to develop some new and remarkable powers. From various parts of the body spring little projections, which soon exhibit an orifice like the mouth of the original Coral, and in a short time this aperture is surrounded with cushions, which are developed into tentacles as before. As soon as it comes to maturity, each of these supplementary Corals puts forth similar buds, so that the increase is wonderfully rapid, even by "gemmation," as this mode of multiplication is called, not to mention the vast numbers of new settlements that are made by the young which are poured from the mouth.

Although we have now learned the method by which the Coral animals are reproduced, we have not ascertained how the solid, stony substance which we call Coral is formed, nor the precise connection which exists between the animal and the Coral.

If the reader will take up a branch of the ordinary Coral of commerce, he will see that it is slightly grooved or fluted throughout its extent, and that its surface is studded with little projections having star-like disks. Now, if this piece of Coral could be again clothed with the living creature by which it was deposited, we should see a beautiful and a wonderful sight. Next to the stony core lie a series of longitudinal vessels, each vessel corresponding with a groove, and above them lies a confused mass of irregular vessels communicating with each other. At intervals there arise the lovely flowerets of the Coral, the bodies being bright rose-color, and their arms pure white. These arms or tentacles are in ceaseless motion, and the aspect of a large and healthy branch of coral is imposingly beautiful.

The animal has the power of depositing certain minute calcareous particles, commonly called spicules, which are always of remarkable forms, and are different in the various species of coral. In the common red Coral they are nearly cylindrical, and armed with projecting knobs covered with angular spikes. These spicules are then bound together by a red cement, and thus the Coral is formed, the fluted branches being deposited under the longitudinal vessels, and the raised projections under the flowerets of the polype. To see the Coral in full vigor it is necessary to visit the spots where it grows, as it dies almost immediately after being taken out of the water, and even if transferred with great care to a vessel, is sure to die in a very short time. After death, the whole of the bark dries up and fades away, so that it crumbles into powder at a touch, and can be removed by merely rubbing the Coral between the fingers.

SEVERAL of the more curious species of Corals and Madrepores are to be seen upon the large illustration, which represents a portion of sea-bed beset with these beautiful zoophytes.

In the upper left-hand corner is the common RED CORAL of commerce, which has been already mentioned, and in the upper centre is a clustered branch of the WHITE CORAL, which is so much used as a drawing-room ornament when placed under a glass shade. In the upper right-hand corner may be seen a singular group of zoophytes with curved stems and flower-like heads. This is the GREEN CLAVELLARIA (Clavellaria viridis), one of the most striking examples of the genus.

The Green Clavellaria is very common on the Isle of Vanikoro,

CORALS AND MADREPORES.

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Corallium rubrum. Tubipora rubeola. Astrea viridis. Clavellaria viridis. Pœcillopora cæspitosa. Xenia elongata.

and is found in tolerably large masses, adhering to rocks, madrepores, and similar substances. All the Clavellarias are of somewhat similar shape, though variable in size and color, and may be recognized by several conspicuous characteristics. The tubes are nearly cylindrical, but tapering, as shown in the illustration, and forming a foot-stalk which is more or less bent.

The texture is somewhat leathery, and is strengthened by innumerable spicules of a calcareous nature, which are agglomerated together in bundles. These spicules are too small to be distinguished except by the microscope, but under a tolerably high power they are seen to be long and spindle-shaped, sharp at both ends, and encircled with little rounded knobs set in regular rows. These tubes are always placed very closely together, but do not adhere to each other, their grooved surfaces being always distinct.

The animal by which this tube is formed is a very pretty one, cylindrical, with eight radiating tentacles of a violet gray. The color of the tube is green for the upper half, and then changes to brown, so that the contrast of the two colors is very decided. The average length of the tube is two inches.

There are several other species of Clavellaria, among which may be noticed the VIOLET CLAVELLARIA (Clavellaria violacea). This is a much smaller species, but is colored in a more bold and decided manner. In this creature the tubes are dark violet and the tentacles are bright yellow. They do not, however, project from the tube as boldly as those of the preceding species, but only just show their tips above the entrance, withdrawing them smartly on the least alarm. As they retreat they slightly contract the orifice, their bodies being fastened to the inside of the tube.

TOWARD the centre of the illustration, and on the right-hand side, may be seen a remarkable tree-like object, covered with long, tendril-like appendages, each tipped with a radiating beard. This zoophyte is known by the title of Xenia elongata, and, on account of its singular form, is a very conspicuous species.

Examples of this genus are spread over many of the hotter parts of the world, some being found in the Red Sea, and all notable for the remarkable form of the animal and its submarine home. The present species has been chosen more for the singularity of its form than the beauty of its colors, which can not be expressed in the simple black and white of a wood-cut. Some species of this genus have the star-like tentacles colored with blue of various shades, some with rose, and some with lilac, and as in many cases the expanded tentacles are an inch in diameter, the effect of a large mass of these animals in full health is very fine.

Except, however, in their native state, they never can be seen in full health, their constitutions being so delicate that they can not endure removal from the spot whereon they were developed. If removed from the water they immediately shrink to half their size, and do not assume their former dimensions, no matter how carefully they are tended. The present species is found on the shores of the Feejee Islands, and in form is certainly the most singular of its genus, the enormously long and slender body at once distinguishing it from any other species. Its color is simple brown, and the diameter of the tentacles is rather more than three quarters of an inch.

In the left-hand lower corner of the illustration is a curious globular object, covered with circular and radiated marks, and having a number of flower-headed projections upon the top. This is the GREEN ASTRÆA (Astræa viridis), one of the finest examples of a singular and beautiful group of zoophytes. In this genus the animals are shaped something like the well-known sea anemone, and rather short, having a great number of very small tentacles, which are gathered round a central mouth. The "cups" which these animals form, and in which they live, are rather deep and conical, and their inner surfaces are corrugated into a number of thin walls with beautifully serrated edges.

The animal is rather oddly formed. The body is not quite cylindrical, but is broader at the base than at the top, and is deeply ridged with circular furrows, so that it looks very like the well-known glass bottles which are used for holding salad dressing, and which make up for lack of contents by profusion of glass. In the very centre of the top is placed the mouth, and round it are grouped a vast number of little tentacles that radiate like the flowerets of a daisy or dandelion. In the present species the animal is about half an inch in length, and the animals are clustered together in masses that are often as large as the fist. They are rather variable in shape, but are always more or less globular.

The color of this species is simple and pleasing. The body of the animal is pale gray-blue, and the tentacles are bright green, so that when a number of the animals are simultaneously protruding themselves, the general effect is very striking. These zoophytes are able to retract themselves almost wholly within their houses, so that nothing is visible except that round the mouth there is a small green circle, which is formed by the projecting tips of the tentacles. This species is found at Vanikoro.