CHAPTER XI. THE ROCK-BUILDERS OF THE OCEAN. "Toil on! toil on! ye ephemeral train, Who build in the tossing and treacherous main; With your sand-based structures and domes of rock. A fabric so vast in a realm so drear! Ye bind the deep with your secret zone; The sea-snatched isle is the home of men, And mountains exult where the wave hath been." Mrs. SIGOURNEY. NE of the most conspicuous wonders of the vast ocean is CORAL, that most beautiful and precious of its productions, which you have no doubt often remarked, without hinking of the cause of its formation and the extraordinary results To which it gives rise. No art can imitate the delicate tracery, the rich colour, and the THE BEAUTY OF CORAL. 133 It has been called by some singular forms that coral assumes. writers "The Queen of the Ocean," and no term could be more appropriate. Ehrenberg, the celebrated naturalist, on viewing the coral-beds of the Red Sea, exclaimed, "Where is the Paradise of flowers that can rival such variety and beauty?" Mr. J. Beete Jukes records his own vivid impressions on seeing some coral-beds in the Pacific: "I had," he says, "hitherto been rather disappointed by the aspect of the coral reefs, so far as beauty was concerned; and, though very wonderful, I had not seen in them much to admire. One day, however, on the lee side of one of the outer reefs, I had reason to change my opinion. In a small bight (a little bay between two points of land) of the inner edge of the reef was a sheltered nook, where the extreme slope was well exposed, and where every coral was in full life and luxuriance." Mr. Jukes describes them as of every shape: some delicate and leaf-like; others with large branching stems; and others, again, exhibiting an assemblage of interlacing twigs of the most delicate and exquisite workmanship. Their colours were unrivalled, vivid greens contrasting with more sober browns and yellows, mingled with rich shades of purple, from pale pink to deep blue. Among the branches, covered with their beautiful drapery of ocean vegetation, floated fish of various colours, radiant with metallic green or crimson, or fantastically banded with yellow and black stripes. Patches of clear white sand were seen here and there, for the floor, with dark hollows and recesses. All these, seen through the clear crystal water, the ripple of which gave motion and quick play of light and shadow to the whole, formed a scene of rarest beauty, and left nothing to be desired by the eye, either in elegance of form or brilliancy and harmony of colouring. I must tell you, however, that it is only in the ocean the glorious homes of the rock-builders are to be seen in perfection, for, immediately after drawing the coral from the water, so rapidly does atmospheric exposure affect them, that it would be difficult to recognize the lovely objects which a moment before were glowing in the still waters. 134 BELIEVED TO BE FLOWERS. "Under spar-enchased bowers Bending on their twisted stems, Twinkle through their crystal halls." Such are the grand and mysterious operations of Providence in the depths of the ocean! I will now describe to you the singular animals to whom the accomplishment of these marvels is due; but I must first mention that coral was formerly supposed to be a marine plant. This ancient notion rested not merely on its shrublike form, but from the circumstance that its branches are covered with a soft coating while in the water, but which dries up immediately on its extraction. Marsilli, an Italian naturalist, perceived in 1707 small objects in the coral-cells, which he thought were flowers; but at length Peyssonnel, a French physician at Marseilles, discovered in 1727 that there was life in the coral, and that these assumed flowers were in reality minute animals. Thus, by the aid of the microscope, an object which might be said to belong to mineralogy, and by its trunk and branches to botany, was now admitted to a rank in the animal world. This discovery of Peyssonnel, the result of thirty years' studious research into the nature of coral, was laughed at by many persons at the time and treated as absurd, but Linnæus, the great Swedish naturalist, saw the truth at once, and did not hesitate to place coral at the head of the zoophytes, or animal plants, an appropriate designation, because it indicates at the same time the double nature of the substances. A common characteristic of these animals is that their mouths are surrounded by radiating tentacles or feelers, appendages by which they attach themselves to surrounding objects, arranged somewhat like the rays of a flower. By this you will understand the term polypi, by which these animals are also known, from the REPRODUCTIVE POWER OF THE POLYP. 135 Greek words polus, "many," and pous, "foot." Of these the individuals of a few families are separate and perfect in themselves, but the greater number of zoophytes are compound beings, or, as I may better explain myself, each zoophyte consists of an indefinite number of individuals, or polyps, connected together. Now, this polyp is an extraordinary creature, and has a tenacity of life truly remarkable. If you cut off the branch of a tree, or sever the limb of an animal, these parts will wither and decompose by passing into other parts of matter. If you cut a tree carelessly, its natural symmetry is disfigured; if you slit it down its centre, it is destroyed. Animals thus treated die, with the exception of the polyp, for it will put forth new limbs, form a new head or tail, and, if divided, become two separate existences. "If," remarks M. Trembley, who was a close observer of these animals, "a polyp be cut in two, the fore part, which contains the head and mouth and arms, lengthens itself, creeps, and eats on the same day. The tail part forms a new head and mouth; at the wounded end shoot forth arms; if turned inside out, the parts at once accommodate themselves to these new conditions. If the body were cut into ten pieces, every portion would become a new perfect living animal. A polyp has been cut lengthways at seven in the morning, and in eight hours afterwards each part has devoured a worm as long as itself! How astonishing it is to see a creature so apparently frail in structure, possessing the actions, sensations, and powers of higher organized beings! The stomach is without membrane or cell; the outside surface-cells form a kind of double skin, and the inside consist of a wall of cells running crosswise, with a velvet-like surface, being red or brown grains held together by a sort of gluey substance." And now let us see how these minute builders of the ocean rocks make their habitations, and form the wonderful coral groves and islands-sometimes hundreds of miles in extent-that we read of. The various species of these animals appear to be furnished with glands (a set of bodies employed to form or to alter the different liquids in the animal body) containing gluten (the basis of glue), converting the carbonate of lime which is in the ocean, and other 136 NATURE OF CORAL. earthy matters, into a fixed and hard substance, twisted—as you observe in coral-in every variety of shape. If you examine a piece of coral with the microscope, you will see that it is covered with a multitude of small pits, which are cells of the most beautiful construction, made with the greatest regularity, and in such a manner that the most experienced builder would pronounce faultless. How this is effected and what peculiar instincts the little toilers of the ocean possess that enable them to construct their dwellings with such mathematical nicety are among those mysteries of Nature we cannot comprehend; but it is certain that large masses of solid rock are framed by these animals, ever working to the music of the waves. "Verily," observes Baker, "for my own part, the more I look into Nature's works, the sooner I am inclined to believe of her even those things that seem incredible." But here we have the certainty of Nature's operations: we know that islands and continents are constructed for the habitation of man by these minute animals; that mountains like the Apennines, and regions to which our own country is but trifling in comparison, are the resuits of their toil. Dr. Mantell remarks, that south-west of Malabar there is a chain of reefs and islets of coral extending four hundred and eighty geographical miles; on the east side of New Holland are unbroken reefs of three hundred and fifty miles long; and between that and New Guinea a coral formation of seven hundred miles in length. The process by which these great changes are effected is still going on extensively in the Pacific and Indian Seas, where multitudes of coral islands emerge from the waves, and shoals and reefs, where the rock-builders are ever busy, appear at small depths beneath the water. How truly wonderful it is to know that the Polynesian Archipelago, now one of the great divisions of the globe, has its foundations formed of coral reefs, the spontaneous growth of once living animals! As one generation of the coral-builders dies and leaves its chalky remains, another succeeds, until the mass of coral appears above the ocean, when the formation ceases, for it is only in that element the labourers can live. |