THE ARGONAUT, OR PAPER NAUTILUS. 



359 



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 larger figure on 

 the right hand represents the Argonaut while thus within its shell. The expanded ex- 

 tremities 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 



ARGONAUT, OR PAPER NAUTILUS. 



Argo. 



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 dicks to- stones or project- 

 ing 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. 



As has already been mentioned, the respiration is achieved by the passage of 

 water over the double gills or branchae ; the water, after it has completed its purpose, 

 being ejected through a moderately long tube, technically called the siphon. The 

 orifice of the siphon is directed towards the head of the animal, and it is by means of 

 this simple apparatus that the act of progression is effected. When the creature 

 desires to dart rapidly through the water, it gathers its six arms into a straight line so as to 



