OF TURBINATED FISHES. 251 



wife, as in quadrupedes. In moft fea fnails, the mouth is placed longi- 

 tudinally, but in feme obliquely, or on one fide. Otheis, of the Trochus 

 kind have no mouth j but a trunk, very long in fome kinds, and fhorter 

 in others. This trunk is flefhy, mufcular, fupple, and hollow. Its ex- 

 tremity is bordered with a cartilage, and toothed like a faw. Thefe are, 

 among fnails, what the tiger, the eagle, or the fliark is among beafls, 

 birds, or fifhes. The whole race of fhelled animals avoid their approach ; 

 though of a thick clumfy fhell themfelves, they move with greater 

 fwiftnefs at the bottom than moft (hell fifli ; and feize their prey with 

 greater facility. No fhell fo large but they will boldly venture to attack 

 it ; and, with their piercing auger-like trunk, will quickly bore it 

 through. No efforts the invaded animal makes avail : if it expand itfelf, 

 and rife to the furface, the enemy rifcs with it -, if it fink to the bottom, 

 its deftroyer clofely adheres. Thus this carnivorous fhell-fifh fticks for 

 feveral days, or weeks, to its prey, until with its trunk it has fucked out 

 all fubftance, or until it drops off when the other begins to putrefy. 



Befide a thick fhell, many fnails are furnifhed with a lid, which opens 

 and fhuts at pleafure. When hunting for food, it opens its box, gropes 

 orfwims about; when fatisfied, drops its lid, and finks to the bottom; 

 where it might be fuppofed in perfect fecurity, but that the trochus 

 breaks into its inclofure. Scarce a fhell is met with entire and found 

 to the end of its convolutions ; but the thinnefl fhells are moft fubject 

 to this invafion. 



Of all fea fnails, that moft frequently feen fwimming, and whofe 

 fhell is thinneft, is the NxAlUTILUS. Whether it is thus employed in 

 efcaping its enemies at the bottom, or in fceking food at the furface, 

 may be doubted. Its ftomach contains chiefly food found at the bottom. 

 Its induftry, therefore, may be owing to its fears ; and its arts of failing 

 may have been originally the produdl of neceffity. 



There are feveral fpecies of the nautilus, yet all may be refolved into 

 two : one with a white fhell, thin as paper, which it often quits, and 

 refumcs ; the other with a thicker fhell, fometimes of a beautiful mother- 

 of-pearl colour, and that quits its fhell but rarely. This fhell outwardly 

 refembles that of a large fnail, but is generally fix or eight inches acrofs: 

 within, it is divided into forty partitions, that communicate with each 

 other by orifices through which one could fcarce thruft a goofe-quill : 

 almoft the whole interior is filled by the animal ; whofe body is divided 

 into as many parts as its fhell has chambers : thefe parts communicate with^ 

 each other, though the openings, by a long blood-vefTeJ, which runs 

 Part V. No. 30. U u from 



