i34 DISSECTION OF THE PIGEON. 



front with the pericardium, and behind with the 

 omentum. 



2. The oblique septum, a fibrous membrane attached to 



the pericardium, and extending backwards^ separat- 

 ing the air-sacs from the general body-eavity. 



3. The heart, which is still enclosed in the pericardium, is 



large and conical, with the apex directed backwards. 

 It lies in the anterior pa.rt of the thorax. 



4. The lungs are spongy bodies lying at the sides of, and 



dorsal to, the heart, and very largely concealed by it. 



5. The liver is a solid lobed organ, of a dark red colour, 



lying behind, and at the sides of the heart. 



6. The great omentum is a fold of mesentery loaded with 



fat, covering the viscera behind the liver. It is con- 

 tinuous in front with the falciform ligament. 



Lift up the great omentum to expose the organs covered 

 by it. 



7. The gizzard is a large firm body, lying immediately 



behind the left lobe of the liver. 



8. The duodenum is a loop of intestine, lying along the 



right side of the abdominal cavity, and embracing the 

 pancreas. 



9. The intestine forms a convoluted mass in the hinder 



part of the abdomen. 



C. The Alimentary Canal. 



Unra/vel the intestine by cutting through the mesentery 

 close to it, but taking care not to tov/;h the duodenal loop. 



Note the veins in the mesentery, which collect the blood 

 from the alimentary canal, and converge to form the portal 

 vein, which enters the liver in the notch between its right 

 and left lobes. 



Note also, and preserve, the posterior mesenteric vein, 

 which runs in the mesenterial fold connecting the rectum with 

 the dorsal wall of the abdomen. 



