78 A MANUAL OF ZOOLOGY 



Three veins enter into the right auricle, two precavae and 

 one postcava. Prom the right ventricle arises the pulmo- 

 nary artery which divides near the heart into two branches 

 which lead directly to the lung. Prom the lungs the blood 

 returns to the left auricle by two distinct pulmonary veins. 

 One large artery, the aorta, comes off from the left ven- 

 tricle. Inflate it through the left ventricle with the blow 

 pipe and trace it out as far as possible. Demonstrate 

 these points and also the valves between the auricles and 

 the ventricles. Trace the digestive system from the mouth 

 , through the oesophagus, the crop, the oAophagus, the 

 proventriculus or fore-stomach, the muscular stomach or 

 gizzard, the duodenum, the small intestine, the large Intes- 

 tine, to the cloaca. The muscular stomach is the most 

 noticeable part of the system. The expansion of the 

 oesophagus' leading into it is the proventriculus. The loop 

 posterior to the gizzard, holding between its folds the long 

 light-colored pancreas, is the duodenum. About an inch 

 from the cloacal end of the intestine are found two little " 

 bud-like diverticula which mark the junction between the 

 large and the small intestine. Emptying into the cloaca 

 from the dorsal side, is a- bag-like diverticulum, the bursa 

 fabrlcii of unknown function. Cut the alimentary canal 

 open longitudinally and note differences in the mucous 

 membrane. Note the contents of the gizzard, the muscu- 

 lar structure of the mucosa, and the teeth. Above and 

 overlapping the sides of the gizzard is the liver. How 

 many lobes has it? Is there a gall bladder? Beneath the 

 gizzard find the spleen. Sketch the digestive system dia- 

 grammatically'; Dissect out the lungs. Note how they 

 are related to the ribs. In the dorsal-posterior part of the 

 body lie the lobulated, brownish kidneys. How many 

 lobes have they? How are they related to the skeleton? 

 Ventral to these In the male lie the two round, light-col- 

 ored testes connected to the cloaca by the two vas defer- 

 ens. In the female, in place of the testes lies the ovary. 

 Leading back to the cloaca find on the left side a single 

 oviduct. How does this compare with the turtle? The 

 oviduct secretes the white of the egg, the enveloping mem- 

 brane, and the shell. Trace the ureters from the kidneys 

 to the cloaca. Make a diagram of the urinary and the 



