CEPHALOPODA. 



307 



course by the assistance of oars provided for the 

 purpose. It is almost a thankless office to dispel so 

 pretty a fiction : modern researches, however, serve 

 to show that its sailing capabilities have been much 

 exaggerated. The Argonaut can certainly raise itself 

 from the bottom and sport about at the surface of the 

 water ; but this is simply effected by the ordinary 

 means used by Calainaries and Cephalopods in 

 general, namely, by admitting the sea-water into its 

 body, and then ejecting it in forcible streams from 

 its funnel, so as to produce a retrograde motion, which 

 is sometimes very rapid. Its usual movements are, 

 however, confined to crawling at the bottom with its 

 head downwards, and in this way it creeps, carrying 

 its shell upon its back, as represented in our Figure. 

 The Nautilus (Nautilus Pompilius). Perhaps the 



FIG. 243. PEARLY NAUTILUS (with the shell in section). 



most remarkable of all the Cephalopods is the 

 Nautilus, the inhabitant of a chambered shell, which 

 is sufficiently common 



" A shell of ample ranp:e, and light 

 As the pearly car of Amphitrite 

 Which sportive dolphins drew." 



