lonia, and Corsica; and the principal parts of the Mediterranean from which coral is obtained, are the coasts of Tunis and Sardinia, and the mouth of the Adriatic. The fishers employ, for this purpose, a very simple kind of machine, consisting of two strong bars of iron or wood tied across each other. From the centre of union of these they hang a weight. Each of the arms is loosely surrounded through its whole length with twisted hemp; and at the extremity there is a small open purse or net. To use this machine, it is suspended by a rope, and dragged along those rocks where the Coral is most abundant. A considerable part of the Coral which is broken off, either becomes entangled in the hemp, or falls into the nets. This operation is usually carried on in places where the water is from eight to ten fathoms deep.

The most valuable Coral, however, as being the largest in size, and most compact in substance, is that which is brought from the East.

OF THE SPONGES IN GENERAL.

The Sponges consist of an entirely ramified mass of capillary tubes, supposed, by many persons, to be the production of a species of worms which are often found straying about the cavities. Others have imagined them vegetables. But that they are possessed of a living principle seems evident, from their alternately contracting and dilating their pores; and shrinking, in some degree, from the touch, when examined in the water. They are capable of absorbing nutriment from the fluid in which they subsist. The species differ much from each other, both in shape and structure. Some are composed of reticulated fibres, or masses, of small spines: some, as the common or officinal Sponge, are of no regular shape; others are cup-shaped, and others tubular.

THE OFFICINAL* AND DOWNY SPONGE†.

The Officinal Sponge is well known, from its utility for various domestic purposes. It is an elastic substance, and in every part is full of holes. It grows into irregular lobes of a woolly consistence, and generally adheres, by a broad base, to the rocks. A variety of small marine animals pierce and gnaw into its irregular winding cavities. These appear on the outside, by large holes, raised higher than the rest. When Sponge is cut perpendicularly, the interior parts are seen to consist of small tubes, which divide into branches as they appear on the surface. These tubes, which are composed of reticulated fibres, extend themselves every way; by this means increasing the surface of the Sponge, and ending at the outside in an infinite number of small holes, which are the proper mouths of the animal. Each of these holes is surrounded by a few erect pointed fibres, that appear as if they were woven in the form of little spines. The tubes, with their ramifications, in the living state of the Sponge, are clothed with a gelatinous substance, properly called the flesh of the animal.

Sponge is an object of commerce in the Mediterranean, and in several of the islands of the Grecian Archipelago. Here, on submarine rocks, it is found, of large size and in great abundance. As it is chiefly found on rocks, at

DESCRIPTION. This well-known kind of Sponge is of irregular form, porous, tough, lobed, and woolly.

SYNONYMS. Spongia officinalis. Linn.-Eponge commune. Bosc.-L'Eponge des boutiques. Cuvier.

+ DESCRIPTION. The tomentous Sponge is porous, of irregular form, brittle, soft, downy, and interwoven with extremely minute spines. When fresh it is of a bright orangecolour, and full of gelatinous flesh: when dry it is whitish, and very light. Linn.-Eponge Velue.

SYNONYMS. Spongia tomentosa.

Bosc.

the depth of five or six fathoms, it has been the cause of many of the inhabitants of these islands having become excellent divers. Yet this fatiguing and dangerous employment does not at all enrich them; for M. Olivier, in his account of Greece, reports that they are in a state of the most lamentable poverty and wretchedness.

When first taken out of the sea, Sponges have a strong fishy smell, which the fishermen get rid of by washing them perfectly clean in fresh water. This is all the preparation which is necessary, previously to their being packed together for sale; but, without it, they would soon become putrid, and perish.

The reproduction of Sponge is more rapid than would, perhaps, be imagined: it is to be found, in perfection, in places from which, only two years before, it had been entirely cleared.

The Downy Sponge is a species very common on nearly all the coasts of Great Britain. It grows round the stalks of several kinds of sea-weeds; and is full of papillæ, or small protuberances. In each of these there is a hole, through which the sponge sucks in and squirts out sea-water, thus giving evident signs of life and motion. When viewed with the microscope, its surface appears composed of an infinite number of minute spiculæ, or prickles, which, if rubbed on the skin, will raise blisters. And it is stated, that this property is much increased if it be dried in an oven.

OF THE SERTULARIÆ, OR VESICULAR

CORALLINES.

The general appearance of all the species of Vesicular Corallines, is exceedingly delicate and beautiful. They have the form of plants, being fixed by a base to submarine rocks, to shells, sea-weeds, or other solid bodies, and usually branching upward in a peculiarly elegant manner. Their stems are composed of a horny or elas

tic and semi-transparent substance, which does not effervesce with acids. These stems are tubulous, and beset throughout with numerous cup-shaped denticles, from which there issue little heads, in the form of polypes. In some of the species the polypes are on one side only of the branches; in others, on both sides; and in others they are verticulate. The colour varies; but the greatest number of them are either white, or of a transparent brown; and nearly all of them become brownish when dried.

The Vesicular Corallines form a very numerous tribe. They are common on all the coasts of Europe. By the ancient naturalists, they were considered to be vegetable productions; but they are now transferred to their proper place, in the animal kingdom.

Some of the species are oviparous, and others produce living offspring.

THE SEA-OAK SERTULARIA

Like all other polypes, the animals which inhabit the Sea-oak Sertularia subsist on marine animalcules, which they arrest, and conduct to their mouth, by means of their tentacula. This Sertularia is found on various species of fuci, or sea-weeds, but chiefly on that which is denominated by Linnæus fucus serratus.

On any alarm, the polypes immediately draw up and conceal themselves within their horny cells. They are sometimes luminous in the dark; for, if the leaf of the plant to which they adhere receive a smart stroke with a stick, the whole Sertularia will be most beautifully illuminated, every point from which a polype issues appearing as if on fire.

DESCRIPTION. In this species the denticles bearing the polypes are opposite, pointed, and bend backward. The ovaries are obovate, and the branches irregular.

SYNONYMS. Sertularia pumila. Linn.-Sertulaire naine

Bosc.

The ovaries of these animals are small, ovate bladders, which adhere to the branches. When the youngones are discharged from the ovaries, they adhere, by their base, to the first object adapted to their wants on which they happen to fall. In this situation they quickly procure, with their tentacula, sufficient nourishment to increase their bulk. The stem soon begins to advance; and many more heads, with their tentacula, issue forth, and stretch themselves out, for the purpose of obtaining food. This causes a further increase of nourishment to be drawn in, which circulates through the whole animal, and enables it to send forth from its base creeping and adhering tubes, full of the same medullary substance with the rest of its body. These tubes secure it from the motion of the waves; and from them arise other young animals, or Sertulariæ, which, growing up like the former, with their proper heads or organs to procure food, send out adhering tubes from below; so that, in a short time, a whole grove of Sertulariæ is thus formed.

OF THE HYDRA OR POLYPE TRIBE.

Polypes are gelatinous animals, which consist of a long tubular body, fixed at the base, and surrounded at the mouth by arms or tentacula. They are chiefly inhabitants of fresh water, and are among the most wonderful productions of nature. The particulars of their life, their mode of propagation, and powers of reproduction, after being cut to pieces, are truly astonishing. Long after experiments had been made, did scepticism involve the philosophic world; and the history of the animals did not obtain complete credit, till these had not only been often repeated, but had been varied in every possible manner.