NECTURUS 69 



Observe the cloaca. Probe through the anus into it. The clo- 

 aca is the common receptacle into which the genital and urinary 

 ducts, as well as the intestine, empty their products. 



Study the liver and pancreas. Observe the lobes of the liver, and 

 the position of the spherical gall bladder under the right lobe. The 

 bile duct joins the liver with the intestine; it emerges from the 

 gall bladder, receives a branch from the liver, and passes through 

 the pancreas to the bend of the duodenum. By squeezing the gall 

 bladder with forceps the dark-green bile can often be forced into 

 the bile duct. 



The pancreas is an elongated organ lying between the duodenum 

 and the stomach. 



Partially embedded in the dorsal surface of the liver will be 

 seen the large postcaval vein ; it runs along the entire length of 

 the liver and receives from it numerous small hepatic veins. The 

 postcaval vein arises between the kidneys, and carries blood from 

 them and from the middle and hinder portions of the body to 

 the heart. 



Exercise 6. Draw a semidiagrammatic sketch of the digestive system, 

 with the liver, the pancreas, and the mesentery. 



Cut the mesentery joining the lungs with the stomach. Remove 

 the stomach, intestine, liver, and pancreas from the body; leave 

 the lungs in the body. 



The Urogenital System. The urinary and genital organs, al- 

 though very different in function, stand in close relation to each 

 other and will be described together. 



The urinary organs consist of a pair of kidneys, a pair of ureters, 

 or Wolffian ducts, which join the kidneys with the cloaca, and a 

 bilobed urinary bladder. The kidneys are narrow and greatly 

 elongated bodies which lie in the hinder part of the abdominal 

 cavity close to the dorsal body wall. The ureter is a convoluted 

 tube which lies against the outer edge of each kidney and opens 

 into the dorsal side of the cloaca. The urinary bladder is a large 

 sac which opens into the ventral side of the cloaca opposite the 

 openings of the ureters. Note the mesentery which joins it with 

 the ventral body wall. 



