CHAP. XIII 



CEPHALOPODA 



379 



Bay of St. Lawrence.^ When excited in the pursuit of fish 

 Ceplialopoda leap high out of the sea. Dr. W. H. Rush^ rehites 

 that when about 300 miles off the coast of Brazil, a swarm of 

 hundreds of decapods flew from the water and landed on the 

 deck of the ship, which was 12 feet above the surface level, and 

 they had to go over the hammock nettings to reach it. 



The common Octopus vulgaris Lam., of British and south 

 European coasts, inhabits some rocky hole, the approaches to 

 which, like the den of a fabled giant, are strewn with the bones 

 of his victims. Homer himself knew how hard it is to drag the 

 polypus out of his hole, and how the stones cling fast to his 



Fig. 238. — Octopus 

 vulgaris Lam., 

 Naples: A, At 

 rest; B, in mo- 

 tion ; /, funnel, 

 the arrow show- 

 ing the direc- 

 tion of the pro- 

 pelling current 

 of water. (After 

 Merculiano.) 



suckers. The colour-changes, which flit across the skin of the 

 Octopus^ appear, to some extent, expressive of the different emo- 

 tions of the animal. They are also undoubtedly protective, 

 enabling it to assimilate itself in colour to its environment. Mr. 

 J. Hornell^ has noticed an Octopus^ while crawling over the rock- 

 work in his tank, suddenly change the colour of the whole right 

 or left side of its body, and of the four arms on the same side, to 

 a snowy whiteness. They have also been seen to change colour, 

 as if involuntarily, according to the material on which they crawl. 



1 Bep. Scotch Fish. ill. 1885, App. F, p. 67. 

 '^ Nautilus, vi. 1892, p. 82. ^ journ. Mar. Zool. i. pp. 3, 9. 



