272 POPULAR CONCHOLOGY. 



takes in its tentacula, wraps its sails over the 

 shell, and descends, blackening the water at 

 the same time, if hard pressed, by a discharge 

 of ink, to cover its escape. During the expe- 

 riments referred to, the animals seemed very 

 shy, and would descend to the bottom on the 

 approach of any person ; except when hungry, 

 at which time they would take food from the 

 hands of Madame Power. 



Division III. — No external shell 

 The four following genera do not form an 

 external shell, and will not therefore be par- 

 ticularly described. 



135. Octopus. — Has two little cartila- 

 ginous pieces in the interior of the body. 



It is found in all seas. 



