CHAP. XIV.] ALIMENTATION. 163 



The large intestine has the usual four coats, except near its 

 termination, where the serous is wanting. The muscular coat, 

 along the caecum and colon, has a peculiar arrangement. The 

 longitudinal fibres are gathered up in three thick bands, and 

 these bands, being shorter than the rest of the tube, the walls are 

 puckered between them. The mucous coat possesses no villi or 

 valvulae conniventes, but is usually thrown into effaceable 

 folds, somewhat like those of the stomach. It contains nu- 

 merous glands, resembling the crypts of Lieberkiihn found in 

 the small intestine. 



Accessory organs of digestion. The accessory organs of diges- 

 tion are, the teeth and salivary glands (which have already 

 been sufficiently described), the pancreas, and the liver. 



The pancreas. The pancreas is a compound, secreting gland, 



FIG. 101. POSTERIOR VIEW OF PANCREAS. 1, pancreas; 2, pancreatic duct; 6, 

 opening of common duct, formed by union of pancreatic and choledochus ducts, into 

 duodenum; A, pyloric end of stomach; B, duodenum ; C, part of gall-bladder; D, 

 cystic duct ; E, hepatic duct ; F, choledochus duct. 



closely resembling the salivary glands in structure, except that 

 the secreting cavities are saccular in the salivary glands, and 

 more distinctly tubular in the pancreas. The cavities are 

 grouped in lobules, each lobule having its own duct. The 

 lobules are joined together by connective tissue to form lobes, 

 and the lobes, united in the same manner, form the gland. 

 The small ducts open into one main duct, which, running 

 lengthwise through the gland, pierces the coats of the duo- 



