XI.J 



THE ALliMEN TA R \ ' 6 Ys 'l 'EM. 



449 



tine of the lowest member of his class the Ornitho- 

 rhynchus. Folds of membrane may be so developed as to 

 form a spiral valve within the intestine, as in Sharks. 



12. The PANCREAS of man is a long, soft, narrow, flattened 

 gland (larger at one end than the other), which lies embraced 

 by a curve of the duodenum. Its excretory duct traverses its 

 length and enters the duodenum a little below the pylorus, 



V.C.T. 



Ao. 



FIG. 380. THE PANCRBAS with its duct (PD\ together with the spleen 



and the splenic artery (SpA). Below this artery is seen the splenic vein 

 running to help to form the vena porta: 



Ao, the aorta ; D, a pillar of the diaphragm ; PD, the pancreatic duct exposed 

 by dissection in the substance of the pancreas ; Dm, the duodenum ; D, the 

 biliary duct opening into the pancreatic duct at x ; y, the intestinal vessels. 



receiving on its road the bile-duct (to be noticed below), so 

 that the two open together into the intestine. The length of 

 tha gland is from six to eight inches. 



13. The pancreas (or sweetbread) of other Mammals may 

 be more developed and complex than in man, as in Bears, 

 and may have two ducts as generally in Dogs. It may pre- 

 sent a beautiful arborescent structure, as in the Hedgehog 

 and Flying Fox. It may be in the form of three long lobes 

 meeting together, as in the Pig. 



The duct may enter the intestine at a much greater dis- 

 tance from the pylorus than in man (as e.g. in the Beaver and 

 Rabbit), and quite distinctly from the bile-duct. 



In Birds the pancreas appears as a narrow elongated 

 gland lodged in the fold of the duodenum, and generally bent 

 upon itself like the gut it adjoins. It has usually two ducts 



G G 



