242 THE PIGEON 



the gizzard, intestine, and other viscera. From the omentum the epigastric 

 vein may be seen passing between the two lobes of the Uver and joining the 

 left hepatic vein, just behind the heart. Notice the two anterior thoracic, 

 the two posterior thoracic, and the two abdominal air-sacs, along the sides 

 of the body under the ribs. 



Make a drawing of the Pigeon, showing the following organs in situ as far as 

 possible : — 



Oesophagus, crop, thymus gland, trachea, muscles of syrinx, heart, liver, 

 gizzard, U-shaped duodenum with the pancreas in its loop, pectoralis major 

 and minor muscles and the position of the pectoral artery and vein and the 

 brachial artery and vein, rectum with the pair of small rectal cffica, and, on the 

 dorsal surface of the cloaca, the bursa Fabricii. {See Fig. 85, p. 240.) 

 Raise the viscera from behind, and notice the following.: — 

 Ovary and oviduct, or testes and vasa deferentia ; kidneys and ureters ; 

 the caudal vein dividing into two " renal portal " veins, and at the point of 

 division a coccygeo-mesenteric vein there arising and going forwards to join the 

 hepatic portal vein which enters the liver ; the " renal portals " receiving the 

 internal iliac veins (from the pelvic wall) and entering the kidneys, and there 

 joined by the sciatic and femoral veins of each side; the "renal portals" 

 issuing from the kidneys as the common iliac veins, which unite to form the 

 posterior vena cava or postcaval vein. 



Second Day 



The Alimentary System. 



Carefully separate the alimentary canal, along its whole course, from the 

 mesenteric attachments, leaving the duodenal loop intact. Notice particularly 

 the various veins and arteries supplying the canal. 



Make a complete sketch of the alimentary canal to show the following 

 parts : — 



(a) The gullet or oesophagus, dilating at the base of the neck to form the 



large thin-walled crop, 

 (fc) The stomach or proventriculus, which secretes the digestive juice. 



A small red body, the spleen, is attached to the side of the 



proventriculus . 



(c) The gizzard, with thick muscular walls. See reference to gizzard 



on page 246. 



(d) 'The duodenum or first part of the small intestine, a U-shaped loop. 



Note the pancreas lying within the loop. 



ie) The three pancreatic ducts, opening into the distal limb of the duo- 

 denum. 



(/) The liver, without a gall-bladder, and consisting of a large right and a 

 smaller left lobe. 



(g) The two bile-ducts, one passing from the right lobe of the liver to the 

 distal limb of the duodenum, the other from the left lobe to the 

 proximal limb of the duodenum. 



