PARTS OF ANIMALS, IV. v. 



it produces this blackness and muddiness in the 

 water, as it were a shield held in front of the body. 

 Now the Calamaries and Octopuses have this ink-bag 

 in the upper region of the body, quite near the mytis'^', 

 whereas in the Sepia it is lower down, against the 

 stomach, since it has a larger supply because it uses 

 it more. This circumstance is due (1) to its living 

 near the land and (2) to its having no other means of 

 defence — nothing like the Octopus, for instance, which 

 has its twining feet, which are useful for this purpose ; 

 it can also change its colour, and it does so (just as 

 the Sepia emits its ink) when put in fear. Of all 

 these, only the Calamary lives well out at sea and gets 

 protection thereby. Hence, compared with it, the 

 Sepia has a larger supply of ink ; and because this is 

 larger, it is lower in the body, as it is easy for it to be 

 emitted even to a considerable distance when the 

 supply is great. The ink is earthy in its nature, like 

 the white deposit on the excrement of birds, and it is 

 produced by these creatures for the same reason — 

 they, like birds, have no urinary bladder ^ ; so the 

 earthiest matter is excreted into this ink, especially 

 in the Sepia, for the Sepia contains an exceptionally 

 large amount of earthy matter. An indication of 

 this is its bone, which is earthy. The Octopuses do 

 not have this bone, and in the Calamary it is cartila- 

 ginous and slight. (We have said why some of these 

 animals have this part and why some have not, and 

 what in each case its character is.) 



These animals, as they have no blood, are cold and 

 liable to take fright. While in some other animals 

 fear causes a disturbance of the stomach, and in some 

 the discharge of residue from the bladder, in these 

 creatures its effect is to make them discharge their 



' 321 



