Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/474

 SHE

SHE

■quent there. Befide thefe, and many other Jhells, there are ■found on this coaft all the fpecies of nautili, many of which are very beautiful.

The Canary ifles are found to abound with a vaft variety of ■the murexes, and fome other good {hells ; and we have, from Madeira great variety of" the echini marini, or fea-eggs, dif ferent from thofe of the European fcas. Several fpecies of mufcles are alfo common there, and the aims marina is no where more abundant.

The Red Sea is beyond all other parts of the world abundant in jbclls, fcarce any kind is wanting there ; but what we principally have from thence are the purpuras, porcelains, and echini marini.

The Mediterranean and northern Ocean contain a great va- riety of -Jbetbi an d many of very remarkable elegance and beauty ; they are upon the whole, however, greatly inferior to thofe of the Eaft-Indies. The Mediterranean abounds greatly more in /hells than the Ocean. The gulf of Tarentum af- fords great variety of purpuras, of porcelains, nautili, and elegant oifters ; the coafts of Naples and Sardinia afford alio the fame, and with them a vaft number of the folens of all the known fpecies. The ifland of Sicily is famous for a very elegant kind of oifter which is white all over ; pinnae •marine and porcelains are alfo found in great plenty there with tellinse and chamas of many fpecies, and a great variety of other beautiful Jhells. Corfica is famous, bevond all other places, for vaft quantities of the pinna; marinas, and many other very beautiful foells are found there. Lijler^ Hift. Conchyl.

About Syracufe are found the gondola-yW/, the alated murex, and a great variety of elegant fnails, with fome of the dolia and neritas.

The Adriatic fea or gulf of Venice is Iefs furnifhed with Jhells than almoft any of the feas thereabout. Mufcles and oifters, of feveral fpecies, are however found there, and fome of the cordiformes or heart-j2v//r ; there are alfo fome ■telling. About Ancona there are found vaft numbers of the pholades buried in ftone, and the aures marinas are par- ticularly frequent about Puzzoli. Bonani Recreat. Meat* et Ocul.

The ports of Marfeilles, Toulon, and Antibes, are full of pinnae marinas, mufcles, tellinas and chamae. The coafts of Bretagne afford great numbers of the conchas anatiferas and poufiepieds, they are found on old rotten boards, on fea- plants, and among clufters of fpunges. The other ports of France, as Rochelle, Dunkirk, .theft, St. Malos, and others, furntfh oifters, excellent for the table, but of the common kind, and of no beauty in theirySf/Zr ; great num- bers of mufcles are alfo found there ; and the common tel- linas, the on ion-peel- oifters, the folens and conchas anatiferas are alfo frequent there. At Granville, in Lower Nor- mandy, there are found very beautiful pecrens, and fome of the cordiforms, or hezxt-fliells. Our own Englifh coafts are not the leaft fruitful in Jhells, though they do not produce fuch elegantly painted ones as the Indies. About Plymouth are found oifters, mufcles, and folens in great abundance ; and there, and on moft of our other ihores are numbers of the aures marinas and dentalia, with pecfens, which are very excellent food ; and many elegant fpecies of the chamae and tellinas are fifhed up in the fea, about Scarborough, and other places.

Ireland affords us great numbers of mufcles, and fome very elegant fcallop-yW/j in great abundance, and the pholades are frequent on moft of our fhores. We have alfo great variety of the buccina and cochleae, fome volutx, and on the Guernfey coaft a peculiarly beautiful fnail, called thence the Guernfey-fnail.

The coafts of Spain and Portugal afford much the fame fpe- cies of Jhells with the Eaft-Indies, but they are of much fainter colours, and greatly inferior in beauty. 'Hift. Nat. Eclairc. p. 172.

There are according to Ta vernier and others fome rivers in Bavaria, in which there are found pearls of a fine water. About Cadiz there are found very large pinnae marinas and fome fine buccina. The ifles of Majorca and Minorca af- ford a great variety of extremely elegant Jhells. The pinnae marinae are alfo very numerous there, and their filk is wrought into gloves, ftockings, and other things. The Baltic affords a great many beautiful fpecies, but particu- larly an orange-coloured pecten, or fcallop-yfo//, which is not found in any other part of the world. The frefh-water-^Z/j are found much more frequentlv, and in much greater plenty than the fea-kinds. There is fcarce a pond, a ditch, or a river of frefh water, in any part of the world, in which there are not found vaft numbers of thefe Jhells with the fifh living in them. All thefe Jhells arc final], and they are of very little beauty, being ufually of a plain greyifh or brownifh colour. Our ditches afford us chamae, buccina, neritas, and fome patellae ; but the Nile, and fome other rivers, furnifhed the antients with a fpecies of tellina, which was large and eatable, and fo much fupcrior to the common fea- tellina m flavour, that it is commonly known by the name of tellina rcgia the royal tellina. We have a fmall fpecies of buccinum common in our frefh waters,

which Is very elegant, and always has its operculum in the manner of the larger buccina ; a fmall kind of mufcle is alfo very common, which is fo extremely thin and tender- that it can hardly be handled without breaking to pieces! The large frefh-water-mufcle, commonly called in England the horje-mujek, is too well known to need a defcription and the fize of this, gives it a difference from all other frefh - water-y7.v/&. Formation of Shells. The world, in genera!, has been much more inquifitive, into the nature of the colours, and marks of the great variety of Jhell-hfti, than what might appear much more worthy of enquiry, the manner of their pro- duction. It has been generally faid, that thefe Jln-lls, and thofe of crabs and lobfters, which are of the cruftaceous kind, were a fort of bones, all of which in thefe creatures are placed by nature on the outfide of the body. It has been fuppofed that both the Jhell and the body of the animal are produced from the 'fame egg, and that, the one developes and enlarges as the other docs. But this, though a fpecious reafoning, does not fcem to be the true ftate of the cafe. On the contrary, it feems, as if the animal alone is produced from the egg, or contained in ■ it, and that the production of the Jhell is a future piece of work- manfhip,

Mr. Reaumur is the firft author who has publifhed an ac- count of the true production of Jhells, and has been at vaft pains to make the neceffary obfervations for this purpofe. He obferved, that the Jhell of the common garden-fnail was plainly made of a vifcous matter, which tranfpired from the body of the creature in a liquid form, and hardened by de- grees on contacl with the air.

It is very well known that all animals continually perfpire, and are furrounded with a fort of atmofpbere of their own, which is of the figure of their body ; and all that is Angular in the perfpiration of fnails, is, that this atmo- fpbere of theirs hardens about them, till it forms a fort of ftony cafe, which being moulded upon their bedy muft be of the fame fhape ; while that of other animals, in general, diffipates itfelf, and is loft among the ambient air,; and this difference plainly arifes wholly from the nature or" the mat- ter perfpired, which in the fnail is of a vifcous, and as it were a ftony nature. It is evident, that this Jhell therefore is not at all of the nature of the bones of animals, being neither formed as they are, nor yet as any other parts of an animal body, but merely by an appofition of particles : fo that we have here an inftancc of a part of an animal body, which borrows its manner of formation from the {tones, and other parts of the foffile world. The head of the fnail is always at the mouth or opening of the Jhell, and its tail at the other extremity, or as we ufually cxprefs it, at the top of the Jhell; and the body of the fnail from whatever caufe, naturally turning itfelf into a fpiral, gives origin to the vo- lutae of the Jhell.

When the fnail is juft hatched naked from the egg, and is in its utmoft degree of fmajlnefs, it does not ceafe to tratt- fpire, and immediately there is formed a Jhell, fuited to its prefent fmall ftate, and exactly fitting every part of its body, which is yet too tender to.. twift itfelf into a fpiral, fo that this Jhell is only the center of that fpiral, which, is afterwards to be formed on that center, with a little part of the fpiral proceeding from it. The animal, after this grows, and if k now ceafed to perfpire, it muft be a ncceflary confequence that the future part of the body muft be naked. This, how- ever, is not the cafe: it continues to perfpire, and every part of the body, as it is, formed, becomes covered with the fame fhelly cruft made by the hardning of that newly per- fpired matter, as it comes in contact with the air. The body of -the fnail, in growing, turns itfelf round the nrft point, and afterwards round that again, ; fo there is fpiral upon fpiral formed, and at the fame time the Jhell is formed in the fame fhape to cover them. The other turns.of the _/7j^ are afterwards formed juft in the fame manner, and thefe in the garden-fnail fometimes. run "as far as to the number four and an half. 1.

It is a neceffary confequence of this manner of formation of thefe Jhells, that the firft circles of a young fnail,whichhas not yet above two of them,. are. of juft the fame fize with the two firft turns of a grown fnail, which has four in the whole ; for whatever part of the Jhell has been once formed, becomes fubject to no increafe in fize afterwards in itfelf, but all the addition to it is made by the continual joining on of more new formed Jhell to its extreme edges. There is, however, an addition of matter to the infides of thefe, to give them a greater itrength afterwards ; for it may always be obferved, that though thefe firft turns, or fpiral wreathes, in a young fnail, are of the fame fize with thofe in a more grown one, yet they are thicker afterwards by much than they are at firft. The new grown part of the animal, which would otherwife have been naked, thus forms Lfelf a coverin* by its perfpiration^ to which the already covered part adds thick- n.efs and ftrength.

In the common fmaller and more beautiful garden-mails, the ground colour of ihejhell is ufually yeUowifn, whitLfh, or reddifh, and is variegated with rays or lines of black, fol- lowing