Genus VI. Calyptr^. 



Genus VI. CALYPTRA— Le Bonnet— Bonnet. 



71. Corrugata— La ChifFonnee — Crumpled — St. Domingo- 

 Patella Equeftris Linn. 



72. Foliacea— La Feuillue— Furbelowed— Japans—Very rare. 



73. Duplicata— La Double— Double, or Cup and Saucer— Ex- 

 tremely fcarce. 



Genus VII. GALERUS— Le Chapeau— Hat. 



74. Chinenfis— Le Chinois — Chinefe — China — Patella Chinen. 

 fis Linn. 



75. Striatus— Le Striee— Striated— Baft Indies. 



Genus VIII. ISgSK— -La Crosse—Crozier . 



76. Spiralis— a. a fection and direction to fhew the cells— 

 L'Ecroue — Scroll— Weft Indies — Nautilus Spirula Linn. 



Genus IX. NAUTILUS— Le Nautille— Sailor. 



77. Pbmpilius— a. young, and umbilicated, or having a navel- 

 like hollow, which goes through the centre of its whirls ; b. young, 

 uncoated, to lhew the pearly part ; c. full-grown, in which ftate 

 the umbilicus, gr hollow, is clofed; d. full-grown,* wmmted : 



fuli-gr^vrfj^and engraved* f^fpartly uncoated, in Angular fcroU 

 worTf*;*^. a^dmeclion, to (hew the interior ftructure.— Le Grand 

 —Great— China, and other parts of Afia. 



The fhells of the genera, or families, 8 and 9, are remark- 

 able for having a number of cells, or chambers, proceed- 

 ing from a fmall beginning, by a moft beautiful gradation, 

 to the largeft fize they have attained. Only the laft, or biggeft, 

 of thefe cells, which is that occupied by the animal when in a 

 living ftate, is vifible till the outer {hell is taken off. Thefe cells 

 communicate with each other by a Syphunculus, or pipe, which 

 in the crozier is teftaceous, and placed on the inner fide, and in 

 the Nautilus partly fhelly, and partly a film, and placed in the 

 centre of the partition which divides one cell from another. 

 This pipe is not continued throughout, but goes only from one paxtx&sor^ 

 <s*fi to another. 



Various have been the conjectures refpecling the ufe of thofe 

 cells unoccupied by the animal ; but the moft prevailing opinion, 

 is, that they are for the purpofe of buoying the ihell to the 

 Surface of the fea, or finking it, at the pleafure of the animal, to 

 procure it food, or efcape danger, by the introduction or expulfioii 

 of either air or water. It has long been a doubt if the Nautili 

 fail on the furface of the fea, as the Argonautse, or Paper Sailors, 

 hereafter mentioned, do ; yet if we confider the outer ftructure 

 8? their {hells, and their great refemblance to the Argonautae, it 



