20 MUSCLES OF THE ABDOMEN 
3. The Cxecum. 
Cut out the cecum together with the adjoining por- 
trons of the small and large intestine, lay open, and 
wash wth water. 
The boundary line between the small and the 
large intestine is marked by a circular thickening of 
the mucous membrane—representing the 2/eo-coltc 
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 cecum 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 rugee. 
5. Lhe Pancreas. lies. m 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 1 or 14 inches 
lower down. (The close attachment of the pancreas 
to the duodenum conceals these ducts. Iihey ‘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- 
