122 INTRODUCTION TO ZOOLOIiY. 



Separate the intestine from the mesentery. Find 

 where the mesentery is attached to the body. 



7. Notice the place at which the small intestine 

 sets into the large intestine. The part of the large in- 

 testine beyond this point is the caecum. How long is it? 



8. Remove the intestine from the abdomen. Find 

 the dorsal aorta running along the backbone. 



9. Find a branch of the aorta going to each kid- 

 ney — the renal arteries, right and left. Do both leave 

 the aorta at the same place? 



10. Find a division of the aorta going to each hind 

 leg. These are the right and left common iliac arteries. 



11. Find the vena cava inferior, running toward 

 the heart parallel tO the aorta. 



12. Find the iliac veins, coming from the hind legs, 

 which veins, by their union, form the inferior vena cava. 



13. Can you find the portal vein, entering the liver? 

 This vein is formed by the mesenteric vein, the splenic 

 vein, from the spleen, and the gastric vein, from the 

 stomach. 



14. Can you find the hepatic vein, from the liver, 

 emptying into the inferior vena cava? 



15. Examine the diaphragm. The thin, transpar- 

 ent portion in the middle is the tendon. Of what is 

 the diaphragm composed? What is its use? 



Organs of the Thoracic Cavity. 



1. Cut through the ribs on eacli side and open the 

 thorax. Identify the heart and the pericardium en- 

 closing it. 



2. Find the auricles. 



3. Trace the aorta. Does it bend to tlie right or to 

 the left? What branches does it give off? 



4. Identify the following arteries : — 



(a) The right subclavian, carrying blood to the 

 right fore leg. 



