DISSECTION OF THE PIG EMBRYO 41 



leading from the gall bladder is the cystic duct. This 

 unites with another small duct, the hepatic duct, to form 

 the common bile duct. The common bile duct empties 

 into the intestine a short distance posterior to the pyloric 

 end of the stomach. Lying along the greater curvature 

 of the stomach is a dark-colored body, the spleen. How 

 is it held in position? Dorsal to the stomach is a 

 whitish body, the pancreas. What is its shape? Posi- 

 tion? A duct leads from the pancreas to the intestine. 

 This is the pancreatic duct, or the duct of Wirsung. It 

 empties into the intestine near the place where the com- 

 mon bile duct empties into the intestine. How is the 

 intestine held in position? The connective tissue that 

 holds the intestine in position is the mesentery. Care- 

 fully remove the mesentery and straighten out the in- 

 testine. Is it a continuous tube? How long is it? 

 What marks the transition from the large to the small 

 intestine? Is there a difference in size between the large 

 and the small intestine? In length? 



Trace the umbilical arteries to their origin. They are 

 branches of the dorsal aorta. A short distance from the 

 aorta the umbilical arteries branch, one part going to the 

 umbilicus and the other going to the hind leg. The one 

 going to the hind leg is the iliac artery. A short distance 

 posterior to the origin of the umbilical arteries the aorta 

 divides into two parts. These are the caudal aortas. 

 Trace the aorta to the diaphragm. Note the branches 

 given off to the kidneys, renal arteries', to the mesentery, 

 superior mesenteric artery, to the liver, hepatic artery, 

 and to the stomach, the gastric artery. 



