A SQUID 131 



prevented from passing into it from the stomach by valves. 

 Loosen the stomach, noticing that it is bound to the ovary or 

 testis by an artery, the genital artery. At the forward end of 

 the stomach are the intestine and the oesophagus, side by side; 

 the former passes between the two halves of the pancreas and 

 ends with the rectum ; the oesophagus goes forward side by side 

 with the anterior aorta to the middle of the large liver and 

 passes through it in company with the aorta. The oesophagus 

 is easily found by turning the stomach over. A small ganglion 

 with radiating nerves will be seen by the side of the oesophagus 

 near its junction with the stomach. 



The liver is an elongated body lying between the retractor 

 muscles of the head and of the siphon; two ducts emerge 

 from it and pass through the pancreas to the stomach pouch. 

 Loosen and remove the connective tissue around the liver and 

 raise it up ; the oesophagus and the aorta will be seen to pass 

 through it towards the back of the animal and then forward to 

 the head. 



Remove the siphon and split the wall of the head ; trace the 

 oesophagus to its forward end. It will be seen to pass through the 

 ganglionic mass which constitutes the central nervous system, 

 and which is surrounded by a hard cartilaginous capsule. For- 

 ward of this it meets and ends in the bulbular pharynx. Near 

 the forward end of the liver, and resting upon the oesophagus, 

 will be seen the median salivary gland, the duct of which may be 

 traced to the pharynx ; near the hinder end of the pharynx is 

 a pair of smaller salivary glands, which also communicate with it. 

 Trace their ducts to the end. The alimentary canal will thus be 

 seen to consist of the following organs : the muscular pharynx, 

 with which a pair of small salivary glands and a single large 

 salivary gland communicate ; the narrow oesophagus ; the thick- 

 walled stomach ; the stomach pouch, which communicates with the 

 stomach by a valved opening ; the elongated liver, which com- 

 municates with the stomach pouch by two long ducts ; the bilobed 



