MOLLUSCS: THE MOLLUSCS 257 



canary birds. The ink is a secretion which the cuttlefish 

 discharges when attacked to create a cloud in the water 

 and thus escape unperceived. The squids (Loligo) com- 

 monly used as bait by fishermen belong to the Decapoda. 

 The two extra feet or arms which the Decapods have in 

 addition to the eight possessed by the Octopods, differ 

 from the others in being longer and slenderer and having 

 suckers only on the distal extremities which are expanded 

 into "clubs " (fig. no). 



The Octopods have a short, sac-like, sub- spherical body 

 and neither external nor internal shell. To this group 



FlG. I jo. The giant squid, Ommatostrephes californica. (From specimen 

 with body (exclusive of tentacles) four feet long, thrown by waves on 

 shore of the Bay of Monterey, California.) 



belong the famous devil-fishes (Octopus], whose strange 

 and terrifying appearance combined with their frequently 

 great size has furnished the basis for many a weird tale of 

 the sea. Octopi have been killed having tentacles more 

 than 30 feet in length. The largest members of the 

 class, however, are probably the giant squids (belonging 

 to the Decapoda) specimens of which have been captured 

 with a body-length of twenty feet, and arms thirty-five 

 feet long. 



The beautiful paper sailor or argonaut (Argonauta argo). 



