450 THE OCEAN WORLD.' 



with a horny or cretaceous margin, and presents in the centre a 



combination of spongy cells. 



Most of the Cephalopods secrete a blackish, inky fluid, to which 



some allusion has been made, but the 

 uses of which, in the economy of the ani- 

 mals, is imperfectly known. The cuttles 

 have considerable quantities of this liquor, 

 which is contained in a sort of sac or 

 ink-purse, placed low down in the abdo- 

 men. When the animal is pursued or 

 threatened with danger it discharges a 

 jet of the fluid, which renders the water 

 thick and muddy, and permits it to escape 

 in the obscurity from its pursuers. It 

 appears that the cuttle-fish avails itself 

 of this stratagem when left accidentally 

 ashore. It is related of an English 

 officer, that, having dressed for dinner. 



Fig. 316. In- Fig. 317. Sepia tuber- . 



ternal bone of culosa (Lamarck). and having SOm.6 time to Spare, he prO- 



Sepia officinalis. ji n V f , 



ceeded along the shore on his favourite 



search for objects of natural history. He reached a hollow rock in which 

 a cuttle-fish had established its quarters ; he soon detected the animal, 

 which looked at him for some time with its great prominent eyes ; 

 in short, they watched each other with fixed attention. This mute 

 contemplation came to a sudden and unexpected termination by the 

 discharge of a voluminous jet of inky fluid, which covered the officer, 

 which was the more unfortunate, since he was in his summer dress of 

 white trousers. 



The ink of the cuttle-fish is a favourite pigment, used in water- 

 colour painting under the name of sepia. It is truly indestructible ; 

 and the hard and black substance found in the sac of fossil species of 

 cuttle-fish when diluted with water produces a brilliant sepia. This 

 property of the inky fluid was well known to the Romans, who used it 

 in making ink. It was long supposed to be the chief ingredient in 

 China ink; but a recent traveller, Mr. Seebold, who has visited 

 the manufactory, and investigated the subject, has revealed the true 

 process by which it is prepared. 



The cuttle-fish affects the sea-shore ; they are along-shore molluscs. 



