THE SINISTER GEPHALOPODS 



After the male's third arm, the Hectocotylus^ has broken 

 away it certainly has power of free movement, for speci- 

 mens have been observed winding and twisting about in 

 water very actively. Kolliker's error was pardonable, for 

 the detached arm acts very much like a worm — much as 

 a living creature with its own individuality. 



The ''shell" of the female argonaut is not a true shell, 

 but really an egg-case, formed between the oval expan- 

 sions terminating the creature's first pair of arms. The 

 arms are held together and a gelatinous substance gradu- 

 ally develops between them which is finely moulded on 

 the inner surface of its membraneous expansion and 

 which slowly hardens in the water to a spiral paper sub- 

 stance, exquisitely embellished with parallel ridges of 

 delicate texture. The two halves of the ''shell" are joined 

 along their lower edges to form a "keel" which is 

 decorated by a double row of brown knobs which are 

 spaced to correspond with the suckers of the arms. 



During the lifetime of its owner the "shell" is elastic 

 and yielding. If carelessly grasped by anyone its extreme 

 thinness and fragility cause it to crumble like extremely 

 thin egg-shell. 



Two of the female argonaut's arms are greatly dilated 

 at their extremities. It was once generally believed that 

 she used these arms as sails, raising them high above the 

 shell, so that the wind filled them and she was driven 

 along by it, while she directed the course of her lovely 

 ship by paddling with her remaining arms, which hang 

 over the side of the curious craft like oars. In consequence 

 of this belief the creature was named the argonaut. 



Certainly she carries a precious cargo. For the female 

 argonaut herself, inside the shell, is a most beautiful 

 creature, despite her seemingly unattractive form. The 

 animal — called the "poulp" — is superficially no more 

 than a shapeless mass, but it is a mass of silver with 

 a cloud of rose-coloured spots. A long semi-circular 

 band of ultramarine blue is clearly marked at one of its 



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