Invertebrate Gallery of the Indian Museum. 133 



the centre of the space enclosed by the bases of the arms 

 is the mouth with its great parrot-like beak. On each side 

 of the head is a large and very perfect eye, and in the 

 space behind and between the eyes is the "siphon". 



Along each side of the oval body is a fold of the 

 mantle which acts as a fin. 



If we cut the body down the antero-dorsal surface — as 

 has been done in one of the exhibited specimens, we come 

 upon the shell or " cuttle-bone ": it lies immediately 

 beneath the skin in a closed cavity formed by an over- 

 growth of the mantle, and has the form of a light oval 

 plate. 



If we open the body from the base of the siphon down 

 the hinder surface, we enter the mantle cavity, in which is 

 seen, on each side, a large gill-plume (coloured in the 

 specimen), and in the space between the gill-plumes the 

 compact globular mass of the viscera, held together in a 

 thin but tough bag. On dissecting this off — the exhibited 

 specimen is a male — we see on the observer's right the 

 reproductive organ, and its duct opening not far from the 

 base of the siphon; on the left the stomach, much con- 

 cealed; and in the middle line the ink-bag, with its duct 

 running alongside the intestine, and ending beside the 

 vent at the base of the siphon. The other viscera apparent 

 are the renal organs : these conceal the heart and great 

 blood-vessels, which lie behind them, but leave unconcealed 

 on each side the great globular dilation of the vein at the 

 base of each gill-plume. 



The secretion of the ink-bag, which is known as sepia, 

 is copiously ejected into the water by the cuttle-fish when 

 molested, in order to cover its escape. 



Cuttle-fishes are found in all seas, in greatest 

 abundance near shore, but sometimes at the surface of the 

 high seas, and sometimes in the depths of the ocean. 

 Their locomotion is effected either by means of the 

 'arms", on which the animal walks head downwards, or 

 by swimming. Some cuttle-fishes, as the Sepia, can 



