20 MUSCLES OF THE ABDOMEN 



3. The Caecum. 



Cut out the ccectim together with the adjoining p07'- 

 tions of the small and large intestine, lay open, and 

 wash with water. 



The boundary line between the small and the 

 large intestine is marked by a circular thickening of 

 the mucous membrane — representing the ilco-colic 

 valve. On one side the mucous membrane of the 

 small intestine is shaggy with villi ; on the other, the 

 colon, the membrane is smooth. The mucous mem- 

 brane of the caecum is thickly studded with small 

 lymph follicles. 



4. The Colon. The mucous membrane is smooth 

 throughout, showing no villi, but in some places it is 

 thrown into irregular folds or rugae. 



5. The Pancreas lies in the loop of the duo- 

 denum ; it is an elongated glandular body of pinkish 

 color. 



6. The Pancreatic Ducts. In the dog there are 

 two main ducts ; one, the smaller, opens into the 

 duodenum about an inch beyond the pylorus, close to 

 or in connection with the bile duct ; the other, larger 

 duct opens into the duodenum about i or i| inches 

 lower down. (The close attachment of the pancreas 

 to the duodenum conceals these ducts. They can 

 be demonstrated most easily by tearing away care- 

 fully the pancreas from the duodenal wall with a 

 blunt-pointed instrument, commencing at the pylorus. 

 The ducts are tougher than the loose connective tissue 

 attaching the rest of the pancreas, and can be ex- 

 posed easily in this way.) 



7. The Spleen is an elongated, flattened, dark- 

 red body lying to the left of the stomach, and con- 

 nected to it by a fold of the peritoneum, the gastro- 



