CLASS I. CEPHALOPODA: ORDER 1. DIB R A NCII I AT A. 495 



Genus ARGONAUTA : Arr/onauta . — This includes the celebrated Paper Nautilus or Ar- 

 gonaut, ^1. ar(jo. Tills is a kind of poulpe or cuttlc-tisli, without any internal skeleton; it has 

 eio'ht arms, provided witli suckers ; two of them are expanded into broad membraneous webs, with 

 whicli 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 bv 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 upon its legs, carrying its 

 house on its back, like a snail 



The Aru'onaut has no muscular attachment to its shell, whence it was formerly supposed that 



the animal took np its residence in a cast- 

 ofl" tenement, as docs 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 cecreting 

 the substance of which they are composed. 

 It has been discovered that if the shell be 

 broken, the animal will set to work Avith its 

 two hands or trowels to mend it ; that it 

 will not only close up cracks, but supply 

 parts that arc 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 (juits its tenement volr.n- 

 tarilv, and asrain resumes it. AVhen in its 

 shell there is a considerable vacuum at the 

 bottom. 



We are indebted for some careful and 

 curious observations on this interesting 

 species to Madame I'ower, 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, shs placed twenty-six of them i;i a vessel and broke the shells in 

 diff 'rent ways. She had the satisiaction 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 mud<ly parts of the bay, where 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. 



ARGONAUT WITHOUT THE SHELL. 



