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articles of food, shell-fish are extensively employe by the poor, and even hold a conspicuous place the tables of the rich. In many places, they, in great measure, support the children of our maritim population; and in the Western and Northern Island of Scotland, have, in years of scarcity, prevente the death of thousands: besides affording emplo ment to several thousands of persons, who are co stantly engaged in searching for shell-fish and brin ing them to market. Independently of the fo which we thus obtain from testaceous bodies, the afford that treasure of a shell,' the pearl, one of t most beautiful ornaments of dress, equally prized the savage and the citizen;-and supply us also wi a dye, the famous Tyrian purple of antiquity, whi constituted an attribute of imperial grandeur. Th we perceive that the study of shells rises in impor ance as we discover its utility. Let us then rega with a more favourable eye the labours of the co chologist, who examines the structure and econon of shells, that, from a more intimate acquaintan with their inhabitants, their nature, and properties, may be enabled to render them still more subservie to our use and pleasure.

Conchology, or Testaceology as it is now som times called, comprises the Mollusca Testacea, soft-bodied animals furnished with shells, being t third order of the fourth class of vermes or worms, the Linnæan system of ZooLOGY. Shells are vided into multivalves, bivalves, and univalves. multivalve shell may be exemplified by any speci of lepas or bernacle, in which the shelly coveri of the animal is formed of several pieces or div sions; the bivalve, by the muscle, in which, as eve one knows, the shell is composed of two pieces valves; and, lastly, the univalve shell, by the comm

For the shell is simple or undivided. The shells are produced from eggs, which in some spee gelatinous, or gluey; and, in others, covered hard or calcareous shell: and the young anierges from the egg with its shell on its back. ost familiar and convincing proof of this may ained, by observing the evolution or hatching eggs of the common garden-snail, as well as eral of the water-snails, which deposit eggs so arent, that the motions of the young, with the on its back, may be very distinctly seen several before the period of hatching.

the shell-animals are of such a constitution as tually to secrete or exude from their bodies a 1 moisture, and it is with this, managed accordthe exigencies of the animal, that the shell is, ghout life, increased in dimensions, and repairhen accidentally broken in any particular part. growth of shells proceeds from the edges of the h or opening, and thus the spires or turns of the lve shells are gradually increased in number ize, till the animal has arrived at its full growth. æus has divided shells into 36 genera; and the amount of species hitherto described is 2445 lusive of varieties), of which 550 are to be found nd around the British Isles. There are many speno doubt, which have not yet made their way the catalogues of conchological writers, and we e reason to suppose that hundreds or thousands - be still unknown.

Multivalves.

Part in their pearly shells, at ease, attend
Moist nutriment; or, under rocks, their food

In jointed armour watch.

. Chiton, coat-of mail shell; inhabitant a doris.

All the chitons are natives of the ocean, and are erally found adhering to rocks or stones that are

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overflowed by the tide; but it possesses the pow of removing from its station. The chiton much sembles the marine woodlouse (oniscus entomor and has often been mistaken for it; and possess the same power of rolling itself into a perfect ball.

2. Lepas, acorn-shell; inhabitant a triton. This genus has been separated into two famili the first containing the balani or bernacle-shells, a the second the lepas or acorn-shell. It is the nat of these shells to adhere in clusters to rocks, she the bottoms of ships, or floating pieces of wo where they are sometimes seen in countless numb Colonel Montagu observed a piece of fir timb above twenty feet long, which was drifted on coast of Devonshire, and which, from end to e was completely covered with them. They app particularly to attach themselves to wood, where t cluster together of all sizes, the smaller adhering, short pedicles, to the larger ones. The animals c tained in these shells, as well as in those of all other species, have each twenty-four claws, or ter cula, all joined in pairs near the bottom, and ins ed in one common base; The twelve longest st somewhat erect and arched, and arise from the b part of the animal. They appear like so many cu feathers, clear, horny, and articulated. Every j is furnished with two rows of hairs on the conc side. They are of use in catching prey, and the mals are continually employed in extending and q tracting them for this purpose. The twelve smal are placed, six on each side, in front of these. T are more pliable and more thickly set with hairs t the others, and seem to perform the office of ha The mouth, formed not unlike a contracted purs placed in front between the smaller claws; and w in its folds are situated six or eight horny lamina erect teeth. Under this lie the stomach and in tines, and the tendons, by which the animal adh

ernacle shells have long been known, in cone of a fabulous notion formerly prevalent, ong those who ought not to have been so dethat from them was bred a species of goose, n in some parts of our island, called the beroose. Of the numerous writers who have ed and credited these circumstances, we shall › accounts only of three, who all speak posion the subject. One of these, Maier, who has a treatise expressly on this bird, says, that it ly originates from shells: and what is still wonderful, Maier says, he opened an hundred Goose-bearing shells in the Orkneys, and found of them the rudiments of the bird completely

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countryman Gerard is another writer on this t; his account of this wonderful transformation all insert in his own words, which have been quoted:- What our eyes have seen, and our have touched, we shall declare. There is a island in Lancashire, called the Pile of Foulwherein are found broken pieces of old and ed ships, some whereof have been cast thither ipwrecks; also the trunks and bodies, with the ches of old and rotten trees, cast up there likewhereon is found a certain spume or froth, that ne breedeth unto certain shells, in shape like e of the muscle, but sharper pointed, and of a ish colour, and the end whereof is fastened unto nside of the shell, even as the fish of oysters and cles are; and the other end is made fast unto the of a rude masse or lump, which in time cometh the shape and form of a bird. When it is pery formed, the shell gapeth open, and the first g that appeareth is the aforesaid lace or string; t cometh the legs of the bird, hanging out; and, t groweth greater, it openeth the shell by degrees, at length it has all come forth, and hangeth only the bill. In short space after it cometh to full

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maturitie, and falleth into the sea, where it gather feathers, and groweth to a fowle bigger than a m lard, and lesser than a goose, having black legs, bill or beake, and feathers black and white, spo in such manner as our magpie, called in some pla pie-annes, which the people of Lancashire call by other name than Tree-goose; which place afores and all those places adjoyning, do so much abo therewith, that one of the best is bought for th pence. For the truth hereof, if any doubt, ma please them to repair to me, and I will satisfy th by the testimonies of good witnesses.'

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The following is Sir Robert Murray's accoun the Bernacle, inserted in the Philosophical Trans tions:-'In the western islands of Scotland, the y ocean throws upon their shores great quanti of very large weather-beaten timber: the most o nary trees are fir and ash. Being in the islan East, I saw lying upon the shore, a cut of a large tree, of about two feet and a half in diameter, nine or ten feet long, which had lain so long ou the water, that it was very dry; and most of the sh that had formerly covered it were worn or rubbed Only on the parts that lay next the ground, there hung multitudes of little shells: they were of the lour and consistence of muscle-shells. This Bar cle-shell is thin about the edges, and about hal thick as broad. Every one of the shells hath so cross-seams or sutures, which, as I remember, vide it into five parts. These parts are fastened to another, with such a film as muscle-shells ha These shells are hung at the tree by a neck, lon than the shell, of a kind of filmy substance, ro and hollow, and creased not unlike the windpipe chicken, spreading out broadest where it is faste to the tree, from which it seems to draw and con the matter which serves for the growth and vegetat of the shell, and little bird within it. In every sl that I opened I found a perfect sea fowl: the little b

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