OTS THE ARGONAUT. 5*25 



far as the anterior edge of the opening. Under whatever cir- 

 cumstances we have observed this mollusc, we have seen it 

 thus disposed. It will be enquired perhaps, how then can 

 it raise itself from the bottom and sport about at the surface 

 of the water, as it is sometimes seen to do ? It is simply by 

 the ordinary means used by calmars and cephalopods in ge- 

 neral ; and which consists in alternately admitting and eject- 

 ing the sea water into and from the dorsal cavity, producing 

 a backward movement, which is sometimes very rapid. 



When the poulp crept upon the bottom of the basin, it 

 presented to us the appearance of a pectinibranchiate gaste- 

 ropod ; the disc which surrounds the mouth and which easily 

 dilates itself to a great extent, being spread upon the surface 

 of the ground like the foot of a gasteropod. The head showed 

 itself above, furnished with lateral eyes and tentacles ; the 

 body concealing itself in a covering shell, whose outer edge 

 shelters in front the tube corresponding to the arms, which 

 like the siphon of a pectinibranchiate mollusc is carried back- 

 wards. The two anterior arms represent the tentacula; and 

 the four lateral arms those tentaculiform expansions, which 

 among the Monodontes and the Litiopes are disposed in a 

 serpentine manner about the animal during its progression ; 

 finally the two posterior arms, carpeting with their lobes the 

 two sides of the shell, merely left between them a narrow 

 space of separation in the median line of the keel. 



It is in this state that we have observed the poulp crawl- 

 ing upon its disc ; but this time it went forward, and its 

 speed was so considerable as to clear a great space of ground 

 in a little time. If anything happened to disquiet it, it re- 

 treated into the shell, which immediately losing its equili- 

 brium, turned over upon its side. 



After this description, should we not be tempted to esta- 

 blish a relation between the cephalopods and the gasteropods, 

 and the poulp of the argonaut on one side, and the Carinaria, 

 Atlantes, &c. on the other ? 



We deceive ourselves perhaps ; but it seems to us that the 

 knowledge we have just obtained of the use of these palmated 

 arms comes in to corroborate the opinion of those who make 

 the poulp the constructor of the shell. What inferences may 

 we not in fact be led to draw from these well established re- 

 lations between the animal and the shell ; from the form of 

 these lobes, which exist in no other cephalopod than the 

 poulp of the argonaut ; and which have never been wanting 

 in those we have been acquainted with, proving that this 

 disposition is expressly on account of the shell ; from the 

 use of these lobes as a mantle, covering the whole in the 



