94 THE MOLLUSCA 



the Argonaut is that given by James Montgomery in his " Pelican 

 Island " : 



" Light as a flake of foam upon the wind, 

 Keel upward from the deep emerged a shell, 

 Shaped like the moon ere half her horn is fill'd ; 

 Fraught with young life, it righted as it rose, 

 And moved at will along the yielding water. 

 The native pilot of this little bark 

 Spread to the wafting breeze a twofold sail, 

 And mounted up and glided down the billow 

 In happy freedom, pleased to feel the air, 

 And wander in the luxury of light." 



Could any description be more dainty and delightful ? Yet not 

 one word of it, I regret to say, is true. The slender arms are 

 never used as oars, while those which have the broad, expanded 

 membranous disk are never used as sails, their real function 

 being to clasp and secrete the fragile shell, depositing the neces- 

 sary shelly matter for its repair should injuries arise. The Argo- 

 naut crawls about on the floor of the sea with its shell on its back 

 in as prosaic a manner as a common garden snail ; while, should 

 it rise to the surface, it swims along backwards by ejecting water 

 from its funnel, after the fashion of the Octopus and Cuttlefish. 

 The male has no shell and resembles a small Octopus, the 

 female alone secreting the shell, which serves as a receptacle for 

 her eggs. 



The members of the Octopus family have only an internal 

 rudimentary and uncalcified shell, consisting of two short styles 

 or plates, enclosed in the body. The eight arms which encircle 

 the front of the head are long and tapering ; they have two rows 

 of disk-shaped suckers, and are united at their base by a broad, 

 membranous web. The mouth is in the centre of the circle of 

 arms, and contains a pair of jaws resembling somewhat in shape 

 the beak of a parrot ; they are not formed of bone, but of a hard, 

 tough material of a chitinous character. The tongue or radula 

 is a slender organ, small in comparison to the size of the animal, 

 beset with rows of sharp-pointed teeth, and is used as a rasping 

 organ to further break up the food that has been torn by the 

 jaws. The head is large and the eyes staring, while the body is 

 more or less bag-shaped, and, besides the digestive organs, con- 



