SF.A-SLUG AND CUTTLE-FISH 



red fluid, which stains the water for the space of a foot around. 

 Besides this means of defence, an acrid secretion, which is 

 spread over its body, causes a sharp, stinging sensation, similar 

 to that produced by the Physalia, or Portuguese man-of-war. 



I was much interested, on several occasions, by watching 

 the habits of an Octopus, or cuttle-fish. Although common in 

 the pools of water left by the retiring tide, these animals were 

 not easily caught. By means of their long arms and suckers, 

 they could drag their bodies into very narrow crevices ; and 

 when thus fixed, it required great force to remove them. At 

 other times they darted tail first, with the rapidity of an arrow, 

 from one side of the pool to the other, at the same instant dis- 

 colouring the water with a dark chestnut-brown ink. These 

 animals also escape detection by a very extraordinary, chameleon- 

 like power of changing their colour. They appear to vary their 

 tints according to the nature of the ground over which they 

 pass : when in deep water, their general shade was brownish- 

 purple, but when placed on the land, or in shallow water, this 

 dark tint changed into one of a yellowish-green. The colour, 

 examined more carefully, was a French gray, with numerous 

 minute spots of bright yellow : the former of these varied in 

 intensity ; the latter entirely disappeared and appeared again 

 by turns. These changes were effected in such a manner that 

 clouds, varying in tint between a hyacinth red and a chestnut 

 brown,^ were continually passing over the body. Any part, 

 being subjected to a slight shock of galvanism, became almost 

 black : a similar effect, but in a less degree, was produced by 

 scratching the skin with a needle. These clouds, or blushes, as 

 they may be called, are said to be produced by the alternate 

 expansion and contraction of minute vesicles containing variously 

 coloured fluids.^ 



This cuttle-fish displayed its chameleon-like power both 

 during the act of swimming and whilst remaining stationary at 

 the bottom. I was much amused by the various arts to escape 

 detection used by one individual, which seemed fully aware that 

 I was watching it. Remaining for a time motionless, it would 

 then stealthily advance an inch or two, like a cat after a mouse ; 

 sometimes changing its colour : it thus proceeded, till having 



' So named according to Paliick Symes's nomenclature. 

 * See Encydop. of Anal, and Physiol, article " Cephalopoda." 



