CONCH OLOGY. 
but there was nothing very remarkable in them. After¬ 
wards, ufing luminous milk, he found that oil of vitriol 
extinguiflied the light, but that of tartar increased it. 
Tiiis gentleman had the curiofity to try-how differently 
coloured lubltances were affefted by this kind of light; 
and having, for this purpofe, dipped l'everal ribbons in it, 
the white came out the brighteft, next to this was the 
yellow, and then the green ; the other colours could 
hardly be perceived. It was not, however, any particu- 
jar colour, but only light, that was perceived in this cafe. 
He then dipped boards painted with the different colours, 
and alfo glafs tubes filled with fubftances of different co¬ 
lours, in water rendered luminous by the pholades. In 
both thefe cafes the red was hardly vifible, the yellow was 
the brighteft, and the violet the dullelt. But, on the 
boards, the blue was nearly equal to the yellow, and the 
green more languid ; whereas in the glades, the blue was 
inferior to the green. 
Of all the liquors to which he put the pholades, milk 
■was rendered the moll luminous. A (ingle pholas made 
feven ounces of milk fo luminous, that the faces of per- 
lons might be diftinguifhed by it, and it looked as if it 
was trnnfparent. Air appeared to be necefl’ary to this 
light; for,.'when Beccarius put the luminous milk into 
glafs tubes, no agitation would make it (hine, unlefs 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 fometimes made more lu¬ 
minous; which they afcribed to the riling of bubbles of 
air through it. Beccarius, as well as Reaumur, had many 
fchemes to render the light of thefe pholades permanent. 
For this purpofe he kneaded the juice- into a kind of pafte 
with flour, and found that it would give light when it was 
immerfed in warm water; but it anl’wered beft to pre- 
ferve the (hell and fifti 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 halted above a-year; and then it would, when plunged 
in warm water, give as much light-as ever it had done. 
Twelve fpecies of the pholas are now afcer-tained by jDr. 
Gmelin. 
LEPAS, the acorn and barnacle (hells.—Thefe (hells 
are moftly quinque-vaives, and are made up of two large 
valves with two (mall ones beneath them,, and a. long nar¬ 
row (pur-like valve which connects them together, and 
runs lengthwife. The Latin name anatifera, was given to 
fome of this fpecies from the fabulous ftory of their be¬ 
coming geefe ; as was alfo the Englifh name barnacle, 
from the fame origin; becaufe the birds they were fup- 
pofed 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 fifti performs its neceffary 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 (hells, 
(tones, or other (olid bodies. There are twenty-eight fpe¬ 
cies of thefe fiiells ; of which the diodema, and anatifera, 
are thought the mo.ft curious. 
CHITON, the ofcabrion. This (hell confifts of many 
parts, loricated, and tied together by articulations, lb 
that the valves fold over each other tranfverfely, like a 
coat of mail. Thefe (bells have.till lately been rejected 
by conchologifts, as approaching too nearly to the cru¬ 
ftaceous animals ; but Linnseus and Dr. Gmelin have fi¬ 
nally decided their fir u flu re to be clearly that of multi¬ 
valve (hells. There are twenty-eight lpscies, fome of 
which are.found near Scarborough, and cn other parts of 
the Britifh coaft. They appertain not only to the Euro¬ 
pean leas, but are found on the coafts of Africa and Ame¬ 
rica, and in the Indian ocean. The moil valued (hells 
are the acule'ated or prickly chiton; the ofcabrion pro¬ 
perly fo called; the magellanic, and Terpentine diadem. 
Thefe clofe the divifion of >iultivalves, which terminates 
our enumeration of all the ihells at prefent known in the 
uni verfe. 
The reader will have noticed what has already been ob- 
fifrved with refpeft to cruftaceous animals, viz. that 
though they are very nearly allied to the teftaceous tribes, 
and in their gradation form (o clofe an affinity with each 
other, yet the great difference in their exterior coverings} 
and the want of thofe distinctive characters in the crufta- 
ceous families, which peculiarly appertain to (bells, have 
induced all the modern naturalifts to rejeft them firm 
every fyftem of eonchology.- There are fome, however, 
who (till infill, that the afterias, or fea ftars ; the rrieducn, 
echinus, &c. are real (lielis, and ftiould, in fpite of fyite- 
matic arrangements, be included as fuch in all our colieo 
tions. This opinion may in fome mealure be deemed ar¬ 
bitrary, and therefore every naturalift wiil decide for 
himfelf. It is our province to follow ftri&ly fyftematic 
writers, efpecially when arrived at fo much accuracy and 
precifion, that diftinffive rules and effential characters are 
eftabliftied, whereby the moll minute objects in the crea¬ 
tion are affigned their proper fcale in the order of nature, 
and whereby the mind is enabled to comprehend and ap¬ 
preciate the different claffes of animated beings, and fur- 
vey without disorder or confufion the boundiefs works 
of the Creator; who, in the -median ifm of the (mailed 
animalcule, has evinced the fame inimitable contrivance, 
that we find in the ftrufture of the molt perfect animals. 
We neverthelels pay due attention to an illuftration of 
the cruftaceous tribes, as arranged in the Linnrean fyftem 
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 
Cofta, in the great view of enabling the young concholc- 
gift to diftinguilh readily, and with precifion, the vary¬ 
ing names, and difcordant methods, of all the principal 
writers on (hells. At the fame time we have directed a 
clear and obvious reference to the terms of the Linnsean 
fyftem, now univerfally received ; and where the reader 
will find, under their refpeCtive titles in this work, the 
natural hiftory and habitudes of thofe numerous animals, 
which are the humble architects of thefe curious and 
beautiful fuperftru&ivres. 
The trivial or technical names of (hells, fo long in ufe 
among conchologifts, have arifen from their fancied re- 
femblance to other objeCts, or from the marks and colours 
of their external coverings. Thus the Panama camp has 
marks upon the (hell formed like the tents of common fol- 
diers ; the pewit’s egg, fpeckled exaCtly like the eggs of the 
plover ; the goat's eye, the garnet, &c. limpets, from the fi- 
milarity of the apices of thofe (hells to a garnet or a goat’s 
eye; fo of the (hield, and Turk’s-cap, limpets. Venus’sear, 
Midas’s ear, and the fea ears, are fo called from their re- 
femblance to the helix of the ear ; pod-horns, from their 
fimilitude to a French horn 5 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 
(hape ; the name of gallery, from its chambered Hru 61 ure, 
is given to the nautilus; the gondola, and la-iler, are 
names for the argonaut, or paper nautilus. Cowries or 
money fheiis, and porcelains, from having the polifh 
and beauty of china, are names for Ihells of the cyprcse 
genus. The weaver’s (buttle is formed much like that 
inftrument; the fea-nuts, the tops, the ftrawberry, and 
onyxes, from an external affinity to thofe objeCts; the 
l'nake, the magpy.ej the painted cockle, See. from their 
pied or party-coloured fpots ; the ray and the tulip, are 
names for ipecies of tellens, from a 1 ikenefs to that 
flower, and to the broken rays of the fun. Partridges, 
are (hells fo called, having a beak or mouth curioufly 
turned like the beak of thole birds; literals, are (hells-lo 
named, becaufe their fpots or marks refemhle the letters 
of lome alphabets. The ducal mantle, is a fpecies of efcal- 
lop, fo named from the richnefs of its colours; the gluts- 
oyiter, from the tranfparency of its valves 5 Venus’s, imply 
Ihells- 
