244 



THE PIGEON 



(h) The small intestine, a long and much-coiled tube. 



(i) The rectum, the short terminal portion of the alimentary canal, opening 



into the cloaca. At its commencement it gives off a pair of small 



rectal caeca. 



Note the coccygeo-mesenteric vein running along the rectum, also the 



mesenteric veins which collect blood from the alimentary canal and combine to 



form the portal vein which enters the liver between the lobes. 



postcaval vein 



Epigastric vein 



Rectum 



'Anus 



Fig. 86. — The Pigeon (Golumha). Dissection showing the 

 Alimentary Canal, the Bile ducts and Pancreatic ducts, 

 and the Posterior Vena Cava, Coccygeo-mesenteric, 

 Hepatic portal, and Epigastric veins. 



, FoUow the course of the trachea down to the lungs, which are spongy organs 

 attached to the anterior dorsal wall of the thorax. The upper portion of the 

 trachea is the larynx (without vocal cords) ; the terminal portion is dilated and 

 forms the syrinx (the vocal organ), and there the trachea divides into two 

 bronchi which enter the lungs. Note that the bronchi are in communication 

 with the air-sacs, and that these are prolonged into several of the bones {e.g., 

 pneumatic cavity in shaft of humerus. See page 252). Notice the thyroid 

 gland, a paired body at the base of the neck. 



Remove the alimentary canal from the body by cutting through the anterior 

 end of the proventriculus and through the rectum, taking care to separate the 

 coccygeo-mesenteric vein from the canal. 



