358 THE AEGONAUT, OR PAPER NAUTILUS. 



In these animals, which are, as has already been mentioned, thought by many 

 naturalists to be above the molluscs, the organization is highly developed. The nervous 

 system is more like that of the vertebrates than is the case with any other kind of 

 mollusc, the knot of ganglia in the head bearing no small resemblance to a real brain. 

 The Cephalopods breathe by means of a pair of gills or branchiae, one set on each side of 

 the body, and the circulating system by which the blood is driven through those organs 

 and thence to the remainder of the structures is very complete. 



They are all animals of prey, and are furnished with a tremendous apparatus for 

 seizure and destruction. . Their long arms are furnished with round, hollow discs, set in 

 rows, each disc being a powerful sucker, and, when applied to any object, retaining its 

 hold with wonderful tenacity. The mode by which the needful vacuum is made is simple 

 in the extreme. The centre of the disc is filled with a soft, fleshy protuberance, which 

 can be withdrawn at the pleasure of the owner. When, therefore, the edges of the disc 

 are applied to an object, and the piston-like centre withdrawn, a partial vacuum is formed, 

 and the disc adheres like a cupping-glass or a boy's leather sucker. 



These discs are all under the command of the owner, who can seize any object with 

 an instantaneous grasp, and relax its hold with equal celerity. The arms are almost as 

 movable and as useful to the cuttle-fish as the proboscis to the elephant, for beside 

 answering the 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 



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 riarrated of its sailing powers. It is rather remark- 

 able, 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 

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

 surface 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-colour, 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 characterises 

 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 mollusc 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" 



