77/ A' ARGONAUT, OR PAPER NAUTILUS. 305 



purposes which have been mentioned, they are also used as legs and enable the creature to 

 crawl on the ground, the shell being then uppermost. 



We will now proceed to a few selected species of Cephalopods, and in the'course of 

 describing the several individuals, will examine the curious points of structure which are 

 common to all. 



DIBRANCHIATA. 



Our first example is the celebrated Argonaut, or Paper. Nautilus, the latter title being- 

 given on account of the extreme thinness and fragility of the shell, which crumbles under a 

 heedless grasp like the shell of an egg, and the former in allusion to the pretty fable which 

 was formerly narrated of its sailing powers. It is rather remarkable, by the way, that the 

 shell of the Argonaut is, during the life of its owner, elastic and yielding, almost as if it were 

 made of thin horn. 



Two of the arms of the Argonaut are greatly dilated at their extremities; and it was 

 formerly asserted, and generally believed, that the creature was accustomed to employ these 

 arms as sails, raising them high above the shell, and allowing itself to be driven over the sur- 

 face by the breeze, while it directed its course by the remaining arms, which were suffered to 

 hang over the edge of the shell into the water and acted like so many oars. In consequence of 

 this belief, the creature was named the Argonaut, in allusion to the old classical fable of the 

 ship Argo and her golden freight. 



Certainly, the Argo herself could not have carried a more splendid cargo than is borne by 

 the shell of the Argonaut when its inhabitant is living and in its full enjoyment of life and 

 health. The animal, or "poulp" as it is technically called, is indeed a most lovely creature, 

 despite of its unattractive form. "It appeared," writes Mr. Rang, when describing one of 

 these creatures which had been captured alive, "little more than a shapeless mass, but it was 

 a mass of silver with a cloud of spots of the most beautiful rose-color, and a fine dotting of the 

 same, which heightened its beauty. A long semi-circular band of ultramarine-blue, which 

 melted away insensibly, was very decidedly marked at one of its extremities, that is of the 

 keel. A large membrane covered all, and this membrane was the expanded velation of the 

 arms, which so peculiarly characterizes the poulp of the Argonaut. 



"The animal was so entirely shut up in its abode, that the head and base of the arms only 

 were a very little raised above the edges of the opening of the shell. On each side of the head 

 a small space was left free, allowing the eyes of the mollusk some scope of vision around, and 

 their sharp and fixed gaze appeared to announce that the animal was watching attentively all 

 that passed around it. The slender arms were folded back from their base, and inserted very 

 deeply round the body of the poulp, in such a manner as to fill in part the empty spaces which 

 the head must naturally leave in the much larger opening of the shell." 



Mr. Rang then proceeds to show the real use of the expanded arms, which is to cover the 

 shell on its exterior, and, as has since been definitely proved, to build up its delicate texture 

 and to repair damages, the substance of the shell being secreted by these arms, and by their 

 broad expansions moulded into shape. The expanded extremities of these arms are seen 

 covering nearly the whole shell, and their bases, set with suckers, are bent bridge-like over the 

 rest of the animal. The large eye is seen just protruding out of the shell, the bases of 

 the arms are curved over and behind it, and some clusters of eggs are seen sheltered under the 

 arch of the expanded arms. 



The modes of progression employed by the Argonaut are to the full as wondrous as its fabled 

 habits of sailing. Its progression by crawling has already been casually mentioned. While 

 thus engaged, the creature turns itself so as to rest on its head, withdraws its body as far as 

 possible into its shell, and using its arms like legs, creeps slowly but securely along the 

 ground, sometimes affixing its discs to stones or projecting points of rocks for the purpose of 

 hauling itself along. 



When, however, it wishes to attain greater speed, and to pass through the wide waters, it 

 makes use of a totally different principle. 



Vol. III.— 39. 



