STRUCTURE OF SEPIA. 337 



A ciliated " olfactory sac " lies behind each eye, and with 

 it a special ganglion is associated. 



Finally, there are tactile or otherwise sensitive cells on 

 various parts of the body, especially about the arms. 



Alimentary System. — The cuttlefish eats food which 

 requires tearing and chewing, and this is effected by the 

 chitinous jaws worked by strong muscles, and by the toothed 

 raSper moving on a muscular cushion. The mouth lies 

 in the midst of the arms, bordered by a circular lip. 

 Through the ganglionic mass passes the narrow gullet, 

 leading into the globular stomach. The stomach is im- 

 mediately followed by another dilatation (" pyloric sac "), 

 and the intestine curves headwards again to end far forward 

 in the mantle cavity. There do not seem to be any glands 

 on the walls of the food-canal, the stomach has a hard 

 cuticle, the digestioij which takes place there must therefore 

 be due to the digestive juices of the glandular appendages. 

 Of these the most important is usually called the liver ; it 

 is bilobed, and lies in front of the stomach attached to the 

 oesophagus. Its two ducts conduct the digestive juice to the 

 region where stomach, " pyloric sac," and intestine meet, 

 and these ducts are fringed by numerous vascular and 

 glandular appendages which are called " pancreatic," as 

 usual without sufficient evidence. Far forward, in front of 

 the large digestive gland, lie two little white glands on each 

 side of the gullet. Their ducts open into the mouth near 

 the radula, their secretion is not known to have any effect 

 on the food. It is obviously better to call them (with 

 Krukenberg) " pharyngeal mucus glands," than to continue 

 repeating the title " salivary glands," for which there is no 

 warrant. At the other end of the food-canal, the ink-sac 

 full of black pigment, probably of the nature of waste- 

 products, opens into the rectum close to the anus. This 

 ink-sac may be called a much enlarged anal gland, for while 

 most of the bag is made of connective tissue and some 

 muscle fibres, a distinct gland is constricted off at the closed 

 end, and the neck is also glandular. 



Vascular System. — The blood of Sepia is bluish, owing 

 to the presence of haemocyanin ^n the serum ; the blood 

 cells are colourless and amoeboid. The median but some- 

 what oblique ventricle of the heart drives the blood forward 



Y 



