ORDER I1.. MONOTHALAMIA. 309 
however, seem specifically distinct from the ‘*Paper Sajlor,”’ nor are any 
of them conchiferous. Another circumstance in the history of these 
animals is, the known paucity of males as compared with females, the 
proporticn being scarcely one in twenty ; they are well known to dwell 
(both sexes together) in deep water, and it has been conjectured that the 
females rise to the surface to receive the warmth and genial influence of 
the sun. The male Argonaut, then, still remains to be discovered. If we 
are to take the naked Octopus of Naples as a mate for the Argonaut, it 
may be no less wonderful than true, that the calcifying membranes, and 
consequently the shell, are a sexual provision peculiar to the female, 
subservient to her generative economy ; a modification in Nature which 
is almost without a parallel. 
The shell of Argonauta may be described as being somewhat boat- 
shaped, and not divided into chambers ; it is papyraceous, very thin, and 
slightly convoluted into a discoid spire, which is doubly carinated and 
partially immersed within the aperture ; the keels are more or less tuber- 
culated 
Example. 
Pl. CCC. 
ARGONAUTA ARGO, Linneus (Gmelin’s edit.), Syst. Nat., p 3367. Mar- 
tini, Conch., vol. i. p. 231. pl. 17. f. 157. 
Navridos, Aristotle. 
Nautilus Nauplius, Bonani. 
Nautilus papyraceus, 1)’Argenville. 
Nautilus tenuis, Knorr. 
Cymbium maximum, Gualtieri. 
Argonauta argo, Linneus, Lamarck, &c. 
We have now completed an arrangement of ‘‘ The Lepades and Conchi- 
ferous Mollusca,’ which, it is much to be regretted, though modelled from 
that of our immortal prototype Lamarck, with all the improvements of sub- 
sequent learning and discovery, is still imperfect for want of a complete 
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