The Chinese have, within the last few years, succeeded in cutting coral beads of much smaller dimension than has hitherto been effected by any European artist. These, which are not larger than small pins’ heads, are called Seed Coral, and are now imported from China into this country, in very considerable quantity for necklaces. There are modes by which Coral may be so exactly imitated, that without a close inspection, it is sometimes impossible to detect the counterfeit.
STONY CORALS.
The Red Coral, just described, belongs to the section of zoophytes called Asteroida by Cuvier, in which the surface of the polypidom is fleshy, and each polypus has only eight arms. The polypi which form the massive stony corals of the tropical reefs, are furnished with numerous tentacles, and resemble in their general conformation the Sea Anemones which are so well known now-a-days as inhabitants of aquaria. The coral consists of a deposit of carbonate of lime, and each polypus dwells in a cell which exhibits a number of thin stony rays nearly meeting in the middle. The masses of coral differ exceedingly in size, some consisting of the habitations of only two or three polypi, whilst others are the gradual production of a vast and constantly succeeding population; some form branched trees and shrubs of the most various and elegant forms, others grow in solid masses, but all, when living, present a most beautiful appearance from the charming and often brilliant diversity of colours with which they are adorned.
In the Pacific Ocean several of the coral reefs are extremely beautiful, and the voyager is astonished with the curious and fantastic forms of the various marine productions of which they are composed. Wheat-sheaves, mushrooms, cabbage leaves, with innumerable plants and flowers, are vividly represented by different kinds of Coral, and glow beneath the water in brilliant tints of brown and purple, white or green; each with a peculiar form and shade of colouring, equal in richness and variety to the most beautiful productions of the vegetable world. Corals and fungi start from between the fissures of the rocks; while large portions of the former, in a dead state, connected into a solid mass, of a dull white colour, compose the stone-work of the reef. Solid masses, termed negro heads, of different dusky hues, and generally dry and blackened by exposure to the weather, are also occasionally conspicuous. Even these are not without ornament, for nature delights in the variety of her decorations. They are studded with small shells, and beautifully marked with outlines expressive of their origin. The edges of the reefs, particularly those exposed to the waves, partake of a considerable degree of lightness, and form small coves and caverns, the resort of live corals, sponges, sea-eggs, and trefangs, or sea traces, (valued in China, for their invigorating quality,) and enormous cockles, which are scarcely to be distinguished from the rock, excepting when they suddenly close their shells, and discharge living fountains, which rise to the height of four or five feet.
With regard to the formation of coral reefs, it has been conjectured, from the appearance of the low islands in some parts of the South Sea and Indian Ocean (where they occur in rows or groups, while they are totally absent in other parts of the same seas), that Coral animals rear their habitations on marine shoals, or, to speak more properly, at or near the top of sub-marine mountains. As it is known, however, that the polypes can only build their coral within a small distance of the surface of the sea, and the water is often of immense depth close to the coral reefs, it has been supposed that in the Pacific Ocean, where the greater part of the Coral reefs and islands are met with, the bottom of the sea has been gradually undergoing changes, deepening in some places and becoming shallower in others, and by this supposition most of the peculiarities of the Coral reefs and islands may easily be accounted for. Where reefs are formed the bottom is generally sinking; islands indicate that the bottom is stationary or rising. In the latter case, when the Corals approach close to the surface, floating substances of every kind are caught by their stony tree-like fabrics, till at length a solid mass of rock is formed, which gradually advances to the surface of the water. The deposits of the ocean no longer tenaciously adhere, but remain in a loose state, and form what is termed by mariners a key upon the summit of the reef; while the sea, by throwing up sand and mud on the top of these animal rocks, progressively raises them above its level. The new island, for such it may now be called, is soon visited by sea-birds; plants successively appear, and carpet the sterile soil with a luxuriant covering. As these decay, vegetable mould is gradually deposited; cocoa-nuts, or some floating seeds, flung on shore by the impetuosity of the waves, take root, and soon begin to grow; land-birds, attracted by the verdant appearance of the bank, fly thither in quest of provisions, and deposit the seeds of shrubs and trees; every high tide and every gale adds some new treasure: the appearance of an island is gradually assumed, and at length man comes to take possession.
CORAL POLYPI, MAGNIFIED.