26 
CONCH 
value ; Tome kinds, as the admirals, kc. have borne afto- 
niftiing - prices when perfect ; and the cedo nulli is fo ex¬ 
tremely rare and beautiful, that this fhell alone has been 
rated at the prodigious fum of one hundred guineas ! See 
Conchology-Plate VI. for this great curiofity. 
The volutes are (hells of a pyramidal or conic (hape; 
the b,afe is flat and wide, and the body rifes gradually 
into a (harp point at the top. The turban is the b’afe, 
and all the whirls are diftinguiftied by flight linear pro¬ 
minences : forne kinds have this bafe quife flat, or a per¬ 
fect helix; in others it prolongs into a (harp clavicle, as 
in the imperial crown,- and. many other fimilar fpecies. 
However, thefe differences of the turban, or clavicle, are 
not eflentiai enough to caufe a fubdiviflon into differ¬ 
ent genera; though Davila’s fecond genus of vo¬ 
lutes which he calls rouleaux, is formed on thefe differ¬ 
ences. The aperture of the volutes runs the whole length 
of the fnell; it is fo extremely narrow as to be linear, be¬ 
ing all along of an equal breadth. The volutes have no 
inner lip. * 
Dr. Lifter calls the volutes rhombi, or flrombi cylin- 
dro-pyramidales. Linnaeus makes the volutes■ and cones 
two diltinif gepera. In the genus conus he places the 
molt convoluted and t urbinated of thefe (hells ; and adapts 
the name of voluta to the mitres, cylindars, and other 
fpiral univalves, that have their pillar plaited or wrinkled. 
Gualtieri calls them cochleae conoideae, or cochleae lon- 
gae; and molt other authors, as Rumphius, Argenville, 
&c. make a diltindt genus of them, by the eltablifhed 
name of voluta. Conedt figures of thefe (hells are exhi¬ 
bited in the annexed engravings. 
GLOBOSAS, or GLOBULAR SHELLS. 
The eleventh family confifts of fltells of a fomewhat 
globoi'e lhape; the body being greatly fwelled, or round¬ 
ed, from whence they acquire the name of globofte, or 
tuns. They have flrort turbans; thfe mouth is extremely 
patulous or wide, and very large; the upper part of it 
«nds iu a wry channel, like a foal’s mouth, which is very 
fliort, and turn§ backwards. - None have a pillar or colu¬ 
mella lip; though in feme, as the Perfian crowns and 
inelotfs, the columella or pillar itl'elf is wrinkled or 
plaited. 
The fpecies which comprife this family, are the tuns-, 
partridges, figs, harps, Perfian crowns, and melons. The 
rank of this family, in fyftematical authors, is, that Lifter 
places thole with a wrinkled or plaited pillar, as the Per¬ 
fian crowns, &-c. among his whelks of the fameftrudture ; 
the tuns and figs among his buccina ampullaceae; and 
the partridges, in a feparate clafs. Linnaeus likewife 
places thole with a wrinkled or plaited pillar, on account 
- of that Itrufture, in the genus voluta; and the partridges, 
tuns-, harps, &c. among his buccina. Rumphius calls 
them cochleae globofie j as does Argenville, who makes 
them, his fourteenth family; Davila-his ninth family, 
and divides them into three genera; Gualtieri has placed 
the figs as cochleae pyriformes ; and the tuns he calls coch¬ 
leae caffldiformes, and caffida. This family is not very 
numerous; but contains many extremely beautiful and 
curious (hells; fome of which are correfilly figured in the 
, copper-plates. 
CASSIDES, or HELMET-FORMED SHELLS. 
The twelfth family is the caflides, orhelmets. Thefe 
are (hells femi-globofe, the back being very convex or 
round,the under, or mouth part, flat. They have either flat 
or very fliort clavicles or turbans. The mouth is long, ra¬ 
ther narrow, and ends at the top in a gutter, which turns 
very large, ltrong, and wry on the back; the lip is always 
ftrcngly and thickly toothed, and rifes into a high thick 
border, or ledge, on the upper part or back; and the pil¬ 
lar is molt generally ftrongly topthed, ridged, or fet with 
I’mall bumps or afperities. 
Some fyftematical authors have agreed with Da Cofta 
in making a diftnfef or particular family of thefe (hells, 
O L O G Y. 
and call them caflides.' Such are Rumphius, Meufclien, 
and Gualtieri. Linnaeus ranks them as buccina; Ar- 
genviile and Davila as murices; and Lifter among his- 
buccina, by the name of bellied or (welled whelks, with 
a wry mouth. This genus is not numerous; but Coma, 
of the fpecies are extremely large and heavy. See the 
annexed engraving. 
TROCHI, or TOP-LIKE SHELLS. 
The thirteenth family is the trochi or tops. Thefe 
are (hells of a conic or pyramidal (hape, the top being 
broad' and flattifti, and gradually tapering thence to a 
very (harp point. The aperture, or mouth, is mod gene¬ 
rally angular, low, and narrow. It is remarkable, that 
all the authors who have written on conchology agree in 
this genus, and in its charadters; fo that few trochi are 
found milplaced. It is a very numerous family, and 
abounds with curious and elegant (hells. 
There is a foflil fpecies of trochus, which feems yet 
undifcovered in a recent date. It is a large kind, flat- 
ti(h, and like a cochlea helix, generally about two inches 
in diameter, and ftrongly and thickly wrinkled, with- 
(harp prominent ridges like plates, which are fplked at 
regular diftances; thefe run acrols the fpires; but the 
whole (hell is likewife'(lightly ftriated. This trochus is 
found in the limeftone of Coalbrookdale, in Shropfliire ; 
and Dudley, in. Staffordfhire. Figures of different fpecies; 
of the trochus are delineated in the annexed engraving.. 
CGCHLEiE, or SNAIL-SHELLS. 
The fourteenth family confifts of the cochleae, or fnails ;■ 
the chara&er of which is a round mouth, or approaching 
thereto, perfectly bordered, circumfcribed, or defined, 
(ore integro.) This family is divided into five genera 5 
viz. 1. Nerits, or fnails with femicircular mouths. 2. He¬ 
lices, or fnails that are flattifti, and whofe fpires lie, as it 
were, between two plains or levels. 3. Snails with a (hort 
or flat turban. 4.. Turbo, or fnails with a produced or 
lengthened turban ; hence called turbines. 5. Cochleae 
ftrombiformes, or fnails whofe turbans are extremely long 
and (lender. All thefe we (hall feparately defcribe. 
NERITA, the NERIT. 
The nerits are (hells whofe mouths are a half circle, 
the columella or inner lip running diametrically acrols 
it in a ftraight line. This lip is very broad or faced, and 
extends greatly on the columella. They are very full- 
bodied (hells, nearly globofe;- and the turban is never 
much produced, but lies flat or level with the bottom* 
The nerits are generally toothed on both lips. 
The (arrangement of this genus in all authors is near to 
or with the fnails; and they are moft generally called ne¬ 
rits. Rumphius calls them cochleae valvatx, and by many 
they are called femilunares. The fpecies of this genus 
are very numerous, admit of great variety, and are gene¬ 
rally beautiful fltells. 
There is found, in a calcareous.fubftance in France, a 
large kind of foflil nerit, called Impet-like nerits. It is a 
very thick (hell, fize of an apricot, and rather flattifti. 
The upper fide is a fine chefnut brown, fomewhat con¬ 
vex, and rifes to a knob or point which is not central, 
but placed Tideways. It is this upper fide that refembles 
a limpet. The under part is milk white, flattilh, and 
round ; the mouth femicircular, the inner lip rifes or 
fwells, expands or faces quite to the upper fide, and is 
armed with two ftrong teeth. It is a very curious fpe¬ 
cies, and is (fill undilcovered in a recent Kate from the 
fea. Several icarce and beautiful fpecies of the nerit are 
given in the annexed copper-plate, from Albertus Seba. 
The HELIX, or SPIRAL SNAIL. 
The effential character of this genus is, that they are 
moft generally round-mouthed fnails, whofe fpires lie ho¬ 
rizontal, or between two levels. Moft of them, being 
land or frelh-wnter (hells } are placed by Lifter among the 
terroftrial 
