304 



CEPHALOPODA. 



robust, and its body is furnished with a fleshy fin 

 running along the entire length of each side. 



The Common Cuttle {Sepia officinalis), numerous on 

 our coasts, is about a foot in length. The colour is 

 a dirty white, but if examined when alive there may 

 be observed a sort of net-work of lines of a reddish 

 or purplish hue playing over the surface, the markings 

 continually changing their form and position, so as 

 to cause a great variety of tints to play over the body 

 of the animal, something like the flickering of a 

 lambent flame. The changes of colour thus pro- 

 duced are quite wonderful. "Although common," 

 says Mr. Darwin, " in the pools of water left by the 

 returning tide, these animals are not easily caught. 

 By means of their long arms and 

 suckers they can drag their bodies 

 into very narrow crevices, and when 

 thus fixed, it requires great force 

 to remove them. At other times 

 they dart, tail first, with the raj^idity 

 of an arrow, from one side of the 

 pool to tlie other, at the same in- 

 stant discolourino^ the water with 

 a dark chestnut-brown ink. 



The shell of the Cuttle-fish, or 

 Cuttle-bone as it is generally called 

 (Fig. 240), is a very curious struc- 

 ture. During life it is enclosed in 

 a cavity of the mantle, wherein it 

 lies quite loose and unattached : it 

 is of an oval shape, and so light and buoyant as to 

 constitute a most elegant float, that doubtless mate- 

 rially facilitates the movements of this otherwise un- 

 wieldy animal. 



Like all the other naked Cephalopods, the Cuttle 

 is remarkable for the ])ower of ejecting, in large quan- 

 tities, a black and inky fluid ; this is contained in a 

 bag, variously situated in different species, and can be 

 spouted out at the will of the animal in surprising 

 abundance, diffusing an impenetrable cloud that ex- 



