EPHALOPOD8. 309 



and frequent rough places, are excellent swim- 

 mers, and move rapidly in the water with their 

 head behind. The cuttle-fish, whose legs are 

 short and body heavy, prefer the bottom, and 

 do not attempt to swim, for which they are not 

 well fitted. Providence has, therefore, given 

 them their long arms to compensate for the 

 shortness of their legs. 



A remarkable peculiarity distinguishes these 

 animals. They are furnished with an organ 

 which secretes a black fluid, with which they 

 can produce an obscurity in the water that 

 surrounds them, on any appearance of danger, 

 or to conceal themselves from their prey. The 

 Chinese are said to use it in making the ink 

 that bears the name of their country ; something 

 similar, but not so black, is prepared from it in 

 Italy ; and Cuvier used it to colour the plates for 

 his memoir on these animals. 



The second order of cephalopods, or at least 

 the pearly nautilus, differs in several respects 

 from those which constitute the first, and which 

 I have just described, approaching much nearer 

 to the Molluscans. The most striking approxi- 

 mation, and which first catches the eye of the 

 examiner is its shell, which, though its spiral 

 convolutions are not externally visible, exhibits 

 a general resemblance to a univalve shell. 

 To a person who had the opportunity of wit- 

 nessing the motions of the animal that inhabits 



