CLASS I. CEPHALOPODA: ORDEE 1. DIBR ANCHIATA. 495 
Genus ARGONAUTA : Argonauta. — This includes the celebrated Paper Nautilus or Ar- 
gonaut, A. argo. This is a kind of poulpe or cuttle-fish, Avithout any internal skeleton; it has 
eight arms, provided with suckers ; two of them are expanded into broad membraneous webs, with 
which the little animal grasps its shell when it is swimming, and by means of which it forms 
and secretes its shell. Formerly these were supposed to be sails, which it spread to the breeze, 
and by means of which it sailed over the sea. This idea, which has often been introduced in 
the poetry of ancient and modern times, is now known to be erroneous. The shell of the argo- 
naut is deeply grooved, and is very thin, transparent, and so flexible when wet that the sides may 
be pressed together. The form is exceedingly beautiful, being somewhat boat-shaped, and the 
little creature floats in it in such a manner that some authors have supposed the art of navigation 
was derived from it. When the creature sinks to the bottom it crawls uj^on its legs, carrying its 
house on its back, like a snail. 
The Argonaut lias no muscular attachment to its shell, whence it was formerly supposed that 
the animal took up its residence in a cast- 
oft' tenement, as does the hermit-crab ; the 
fact is now well ascertained that its shell 
is formed by the membranes above men- 
tioned, which have the power of secreting 
the substance of which they are composed. 
It has been discovered that if the shell be 
broken, the animal will set to work with its 
two hands or trowels to mend it ; that it 
will not only close up cracks, but supply 
parts that are broken away, with the same 
material as that which composed the origi- 
nal fabric. In repairing its shell it will 
even take advantage of pieces of shell that 
come in its way, and solder them in to fill 
up a crevice. It appears that the little 
animal is extremely sensitive, and some- 
times in fright it becomes separated from 
the shell, and consequently dies; it how- 
ever occasionally quits its tenement volun- 
tarily, and again resumes it. When in its 
shell there is a considerable vacuum at the 
bottom. 
We are indebted for some careful and 
curious observations on this interestiup- 
species to Madame Power, who resided at 
Messina, and for several years devoted her- 
self to the study of these animals. In order 
to determine whether the shells really were 
produced by these creatures, she placed twenty-six of them in a vessel and broke the shells in 
dift"erent waj^s. She had the satisfaction of seeing them immediately proceed to cover the broken 
parts with the sails, and by wrinkling them upon the parts, close the fractures. The first day 
the new substance was thin and delicate as a cobweb, but it thickened and hardened gradually, 
until in about thirteen days it had become perfectly firm, and shelly as the unwounded part, though 
somewhat more opaque. 
The Argonaut is a native of various seas, but it is most common in the Mediterranean, and 
especially in the vicinity of Messina ; here it is found, even in the port, all the year, but is most 
abundant in autumn, and in the muddy parts of the bay, Avhere the boats lie thickest. When 
on the surface, if they observe any person, they fold the sail-arms over the shell, dispose the row- 
ing arms within it, and sink. If they happen to be beneath, when alarmed, they eject their ink, 
ARGONATIT WITHOUT THE SHELL. 
