98 • . iv, 5. 



In some Testacea, as was said in the ^ first treatise, the organ 

 which is called the tongue is of considerable strength ; and In 

 one kind, namely the Sea-snails, in addition to the tongue there 

 are two teeth,'" resembling those of the Crustacea. The mouth 

 in the Cephalopods ^^ is succeeded by a long gullet. This leads 

 to a crop, like that of a bird. Directly continuous with this is 

 the stomach, from which a gut runs without windings to the 

 vent. The Sepias and the Poulps resemble each other completely, 

 so far as regards the shape and consistency of these parts. But 

 not so the Calamaries. Here, as in the other groups, there are 

 two stomach-like receptacles ; but the first of these cavities has 

 less resemblance to a crop, and in neither is the form or the 

 consistency the same as in the other kinds, the whole animal 

 indeed being made of a softer kind of flesh. 



The object of this arrangenient of the parts in question is the 

 same in the Cephalopods as in Birds. For in neither of these 

 groups is the* mouth suited for mastication ; and therefore it is 

 that a crop precedes their stomach. 



For purposes of defence, and to enable them to escape from 

 their foes, the Cephalopods have what is called an ink-bag 

 attached to their body. This is a membranous pouch, which 

 is provided with a terminal outlet just at the point where what 

 is termed the funnel gives issue to the residua of the stomach. 

 This funnel is placed on the ventral surface of the animal. All 

 Cephalopods alike have this characteristic ink-bag, but chief of 

 all the sepia, where it is of greater size than in the rest.'^ When 

 the animal is disturbed and frightened it uses the ink to make 

 the surrounding water black and turbid, and so, as it were, puts 

 a shield in front of its body. 



In the Calamaries and the Poulps the ink-bag is placed in 

 the upper part of the body, in close proximity to the mytis}^ 

 whereas in the sepia it is much lower down, against the stomach. 

 For the sepia has a larger ink-bag than the rest, owing to its 

 making more use of it. The reasons for this are, firstly, that it 

 lives near the shore, and, secondly, that it has no other means 

 of protection ; whereas the poulp has twining feet ^* that it can 

 use in its defence, and is moreover endowed with the power of 

 changing its colour.'^ This changing of colour, like the discharge 

 of ink, occurs as the result of fright. As to the calamary, it 

 lives far out at sea, being the only one of the Cephalopods that 

 679 a. 



