THE LIVING STRUCTURES 



121 



hard material. Its size is up to three feet in length, so it 

 is small enough to have a number of enemies. It is pro- 



FIG. 17. Sepia cultrata or cuttle-fish. Entire animal viewed from the dorsal 

 aspect. 



vided with a sack of black material like ink, which it 

 throws into the water behind it when pursued by ene- 

 mies and in this way it escapes very easily. It has long 



