UNIVALVE SHELLS. 
PAPER NAUTILUS. 
GENERIC CHARACTER. 
A thin ribbed shell with a large single cavity. 
SPECIFIC CHARACTER. 
Argonauta Argo. A. carina utrinque subdentata. Linn. Syst. 
Nat. Gmel. 1. p. 3867* 
Keel a little toothed on both sides. 
Nautilus tenuis. Rumph. Mus. pi. 18. 
f. 1, 4. A. B. 
Nautilus papyraceus. Argenv. Conch. 
pi. 5. f. A. B. C. 
Paper Nautilus. List. Conch, pi. 55 4, 555. Seb. Mus. 3. 
pi. 84. f. 4 — 12. 
This shell is one of the most elegant of the whole 
tribe, and is remarkable for the thinness of its sub- 
stance ; it is of a pure white, except a slight tinge 
of yellow within the shell, and the sides are marked 
with elegant ribs that run towards the keel. This 
little vessel has a sailor within who has been much 
