CONCHOLOGY. 



3,5 



feot there was notlihig very remarkable in them. After- 

 wanls, ufmg luminous milk, he found that oil of vitriol 

 extinguiflied the light, but that of tartar increafed it. 



Tnis gentleman had the curiofity to try how diftarently 

 coloured lubllunces were atFefted by this kind of ligli! j 

 and having, for this purpofe, dipped feveral ribljons in it, 

 the white came out the brigbteft, next to this was the 

 yellow, and then the green ; the other colours could 

 hardly be perceived. It was not, however, any particu- 

 lar colour, but only liglit, that was perceived in this cafe. 

 He then di^iped boards painted with the dirferent colours, 

 and alio glals tubes filled with fubftanccs of different co- 

 lours, in water rendered luminous by the pholades. In 

 both thefe cafes the red was hardly vilible, the yellow was 

 the brightelf, and the violet the dullell. But, on the 

 boards, the blue was nearly equal to the yellow, and the 

 green more languid ; whereas in the glaffes, the blue was 

 inferior to the green. 



Of all the liquors to which he put the pholades, milk 

 ■was rendered the moll luminous. A fingle pholas made 

 fcven ounces of milk fb luminous, that the faces of per- 

 fons might be diltinguilhfd by it, and it looked as if it 

 was tranfpareiit. Air appeare;! to be necelVaiy to this 

 light; for, when Beccarius put the luminous milk into 

 glafs tubes, no agitation would make it fhine, unlcl's bub- 

 bles of air were mixed with it. Alfo Montius and Ga- 

 leatius found, that, in an exhaufted receiver, the pholas 

 loft its light, but the water was lometimes made more lu- 

 minous ; which they alcribed to the rifmg of bubbles of 

 air through it. Beccarius, as well as Reaumur, had many 

 i'chemes to render the light of thefe pholades permanent. 

 For this puipofe he kneaded the juice into a kind of palle 

 with flour, and found that it would give light when it was 

 immerled in warm water; but it aniwered bed to pre- 

 lerve the (liell and fifli in honey. In any other method of 

 prefervation, the property of becoming luminous would 

 not continue longer than fix months, but in honey it 

 had lalled above a-year; and then it would, when plun'^ed 

 in warm water, give as much light as ever it had done. 

 Twelve Ipecies of the pholas are now afcertained by Dr. 

 Gnielin. 



LEP.-^S, the acorn and barnacle fhells. — Thefe (liells 

 are moftly quinqiie-valvcs, and are made up of two large 

 valves with two hnall ontrs beneath them, and a long nar- 

 row fpur-like valve which conneth them together, and 

 runs lengthwife. The Latin name anatij'era, was given to 

 fome of this fpecies from the fabulous Itory of their be- 

 cominsj geefe ; as was alfo the Englilh name bani.tcle, 

 from the fame origin; becaule the birds they were lup- 

 poled to produce were the barnacles or brent geele. 



The balani are made up of many valves lying parallel 

 to each other, and in a perpendicular pofition, contrary 

 to the pofition of all other valves, which lie horizontally. 

 The top is open, and the filh performs its neceliary func- 

 tions by that aperture ; for the valves never open or fe- 

 parate, as they have no hinges. The bottom is the part 

 by which they affix themfelves to other bodies; for the 

 balani are never found loofe, but affixed to large fliells, 

 ftones, or other folid bodies. There are twenty-eight fpe- 

 cies of thefe fliells ; of which the diodema, and anatifera, 

 are thought the moft curious. 



CHITON, the olcabiion. This fliell confills of many 

 parts, loricRted, and tied together by articulations, ib 

 that the valves fold over each other tranfverfely, like a 

 coat of mail. Thefe (hells have till lately been rejetled 

 by conchologifts, as approaching too nearly to the cru- 

 ftaceous animals ; but Linnaeus and Dr. Gmelin have fi- 

 nally decided their Urufture to be clearly that of multi- 

 valve fliells. There are twenty eight fpedes, fome of 

 which are found near Scarborough, and on otiier parts of 

 the Britifh coaft. They appertain noj only to the Euro- 

 pean leas, but are found on the coafls of Africa and Ame- 

 rica, and in the Indian ocean. The moll valued (hells 

 are the acule.ited or prickly chiton ; the ofcabrion pro- 

 perly lb called j the magellanic, and ferpeatine di.idem. 



Thefe clofe the divifion of multi valves, which terminates 

 our enumeration of all the fliells at prefent known in the 

 univcrfe. 



The reader will have noticed what has already been ob- 

 ferved with relpeft to crullaceous animals, viz. that 

 though they are very nearly allied to the tedaccous tribes, 

 and in their gradation form fo clofe an afiinity with each 

 other, yet the great dilference in their exterior coverings, 

 and the want of thole dilUn6live charatlers in the crulla- 

 ceous families, which peculiarly appertain to fliell?, have 

 induced all the modern naturalilts to rejeft them hom . 

 every fvllem of conchology. There are fome, however, 

 who dill infill, that the alterias, or lea liars ; the meduca, 

 echinus, &c. are real fliells, and (hould, in Ipite of fyfte- 

 matic arrangements, be included as fuch in all our collec- 

 tions. This opinion may in fome mealure be deemed ar- 

 bitrary, and therefore every naturalill will decide for 

 himfelf. It is our province to foilovv lliiiSiiy fyllematic 

 writers, efpecially when arrived at fo much accuracy and 

 precifion, that diftinftive rules and cflential charailers are 

 eftabliflied, whereby the mofl: minute objefts in the crea- 

 tion are afligned their proper fcale in the order of nature, 

 and whereby the mind is enableil to comprehend and ap- 

 preciate the different clafles of animated beings, and fur- 

 vey without dilbrder or confufion the boundiefs works 

 of the Creator; who, in the methanifm of the fmallefr 

 animalcule, has evinced the fmie inimitable contrivance, 

 that we find in the Itrno^ure of the mofl: perfeil animals. 

 We neverthelels p.ay due attention to an illullration of 

 the crullaceous tribes, as arranged in the Linnjean fyfteni 

 by Dr. Gmelin ; in proof of which we beg to refer the 

 reader to the articles Asterias, Cancer, Echinus, &c. 

 In the prefent treatife we have principally followed Da 

 Coda, in the great view of enabling the young concholci- 

 gift to didinguifli readilv, and with precifion, the vary- 

 ing names, and difcordant methods, of all the principal 

 writers on (hells. At the fame time we have dire<Jted a 

 clear and obvious reference to the terms of the Linnsean 

 fyltem, now univerfaily received ; and where the reader 

 will find, under their refpertive titles in this work, the 

 natural hidory and habitudes of thofe numerous animals, 

 which are the humble architecls of thefe curious and 

 beautiful fuperftruilures. 



The trivial or technical names of fliells, fo long in ufe 

 among conchologills, have arilen from their fancied re- 

 femblance to other objeils, or from the marks and colours 

 of their external coverings. Thus the Panama camp has 

 marks upon the fliell formed like the tents of common fol- 

 diers ; the pewit's egg, fpeckled exaflly like the eggs of the 

 plover ; the goat's eye, the garnet. Sec. limpets, from the fi- 

 milarity of the apices of thofe (hells to a garnet or a goat's 

 eye; fo of the fliield, and Turk's-cap, limpets, Venus'sear, 

 Midas's ear, and the fea cars, are fo called from their re- 

 femblance to the helix of the ear; pod-horns, from their 

 fimilitude to a French horn; elephant's tooth, from its. 

 cylindric tapering form and curvature; the ram's-horn, 

 is a name for the lituus, on account of its convoluted 

 fliape; the name of gaiitry, from its chambered llruiture, 

 is given to the nautilus; the gondola, and failer, are 

 names for the argonaut, or paper nautilus. Cowries or 

 money (hells, and porcelains, from having the polilh 

 and beauty of china, are names for (hells of the cypress 

 genus. The weaver's fliuttle is formed much like that 

 indrument; the fea-nuts, the tops, the drawberry, and 

 onyxes, from an external afiinity to thofe objedls ; the 

 fnake, the magpye, the painted cockle, Sec. from their 

 pied or party-coloured fpots ; the ray and the tulip, are 

 names for ipecies of teilens, from a likenefs to tftat 

 fiovi-er, and to the broken rays of the fun. Partridges, 

 are fliells Ib called, having a beak or mouth curioufly 

 turned like the beak of thofe birds; literals, are fliells lo 

 named, becaule their fpots or marks refemble the letters 

 of (ome alphabets. The ducal mantle, is a fpecies of efcal- 

 lo;), fo named from the richnefs of its colours; the glafs- 

 oylier, from the traiifparency of its v.ilves ; Venus's, imply 

 - ftells 



