Genus VI. Calyptra. 
S 
Genus VI. CALYPTRA — Le Bonnet— -Eonnet. 
71. Corrugata— La Chiffonnee — Ci*umpled — St. Domingo 
Patella Equeftris Linn. 
72. Foliacea— La Feuillue — Furbelowed— Japan — Very rare. 
7 3. Duplicata— La Double — Double, or Cup and Saucer — Ex- 
tremely fcarce. 
Genus VII. GALERUS— Le Chapeau — Hat. 
74. Chinenfis — LeChinois — Chinefe — China — Patella Chinen- 
fis Linn. 
75. Striatus— Le Stride — Striated — Eaft Indies. 
Genus VIII. LI — La Crosse — Crozier. 
76. Spiralis — a. a fedtion and difledtion to Ihew the cells— 
L’Ecroue — Scroll — Weft Indies — Nautilus Spiruia Linn. 
Genus IX. NAUTILUS — Le Nautille — Sailor. 
77. Pompilius — a. young, and umbilicated, or having a navel- 
like hollow, which goes through the centre of its whirls ; b. young, 
uncoated, to {hew the pearly part; c. full-grown, in which ftate 
the umbilicus, or hollow, is doled; d. full-grown, uncoated: 
e. full-grown, and engraved ; f. partly uncoated, in Angular fcroll 
work ; g. a difledtion, to {hew the interior ftrudture. — Le Grand 
—Great— China, and other parts of Alia. 
The {hells 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 lhell 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 flielly, 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 
cell to another. 
Various have been the conjedtures refpedHng the ufe of thofe 
cells unoccupied by the animal ; but the moft prevailing opinion 
is, that they are for the purpofe of buoying the {hell to the 
fiirface of the fea, or finking it, at the pleafure of the animal, to 
procure it food, or efcape danger, by the introdudtion or expulfion 
of either air or water. It has long been a doubt if the Nautili 
fail on the furface of the fea, as the Argonautas, or Paper Sailors, 
hereafter mentioned, do; yet if we confider the outer ftrudture 
of their {hells, and their great refcmblance to the Argonauts?, it 
