Genus VI. Calyptra. 



I 



^ Genus VI. CALYPTRA— Le Bonnet— Bonnet. 



71. Corrugata— La ChifFonn6e— -Crumpled— St. Domiiigo— ^ 

 Patella Equeftris Linn, 



73. Foliacea— La Feuillue—Furbelowed— Japan— Very rare, 



73. Duplicata—La Double— Pouble, or Cup and Saucer— 

 treme-ly fcarce. 



/ Genus VIL GALERUS— Le Chapeau— Hat. 



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

 fis Linn. 



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



/ Genus VIIL^^^^SH—La Crosse— Crozjer. 



76. Spiralis— a, a feflion and difTeftion to Ihew the cells—- 

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



Genus IX. NAUTjSuS— Le Nautii,i.e— Sailor, 



77. Pompilius — a, young, and umbilicated, or having a naveH- 

 iike hollow, which goes through thexentre of its whirls ; L young, 

 uncoated, to ftiew the pearly part ; c. full-grown, in whieh ftate 

 the umbilicus, or hollow, is clofed; d. full-grown, mia i Qtft^-; 

 e. fuU-prownJ^liid engraved j'TTl^rtly uncpated, in Angular fcroU 

 ywvyr- iTa^difleclion, to ftiew the interior ftruaur?.— Le Grand 

 —Great— China, and other parts of Afia. 



The ftaells 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 ftiell 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 ftielly, 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 partition 

 «3|;l to another. - 



Various have been the conje^lures refpefting the ufe of thofe 

 cells unoccupied bv the animal ; but the moft prevailing opinion 

 is, that they are 'for the purpofe of buoying the ftiell to the 

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

 procure it food, or efcape danger, by the introdudlion or expulfioij 

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

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

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

 of their fiiells, and their great refemblance to the ArgonautjE, it 



