DIGESTIVE SYSTEM. 437 



uniform diameter, and about two feet and a half in 

 length. 



6. The rectum, or terminal portion of the intestine, is about 

 an inch and a half long. Its commencement is 

 marked by a pair of small csecal processes, the rectal 

 diverticula. Posteriorly, the rectum opens into the 

 cloaca, the examination of which should be deferred 

 until the kidneys have been dissected. 



D. The Liver. 



The liver is divided into a larger right, and a smaller left 

 lobe, the surfaces of which are hollowed and grooved to re- 

 ceive the heart, duodenum, and gizzard. 



The bile-ducts are two in number, and open into the 

 duodenum. 



1. The left bile-duct is a wide tube, about an inch long, 



which, emerging from the notch between the right 

 and left lobes of the liver, runs backwards to open 

 into the proximal limb of the duodenum, about half 

 an inch beyond the gizzard. 



2. The right bile-duct is longer and narrower. It leaTes 



the liver near the dorsal margin of the right lobe, 



Fia. 73. — Columba livia. Dissection of the male from the right side. 

 Half the liver and the greater part of the intestine have been 

 removed. In the right wing, the bones and the arrangement of the 

 primary and secondary feathers are shown. The reproductive 

 organs are omitted, (a. m. m.) 



A, nostril. AD, ad-digital primary feather. B, external auditory meatus. 

 B'W, bastard wing, C, oesophagus. CA, right carotid artery. D, crop. 

 DA, aorta. E, keel of the sternum. F, right auricle. Gr, right ventricle. 

 HV, hepatic vein. H 1, left bile-duct. H 2, right bile-duct. I, distal end of 

 proventricxilus or stomach. I A, right innominate artery. IV, posterior vena 

 cava. JA, left innominate artery. JV, right jugular vein. K, gizzard. 

 Xi, liver. M, proximal limb of duodenum. MD, the two mid-digital primary 

 feathers. MP, the six metacarpal primary feathers. M 1, preaxial metacarpal. 

 M 2, middle metacarpal. M 3, postaxial metacarpal. K", cloacal aperture. 

 W 1, preaxial digit of manus. O, bursa Fabricii. 1, proximal phalanx of middle 

 digit of manus. O 2, distal phalanx of -middle digit of manus. P, pancreas. 

 PA, right pectoral artery. PD, pre-digital primary feather. PV, portal 

 vein. P 1, first pancreatic duct. P 2, second pancreatic duct. P 3, third 

 pancreatic duct. Q, pygostyle. R, Rectum. RC, radial carpal bone. 

 RX, rectrices or tail feathers. R 1, ulnar digit of manus. S, ureter. 

 SA, right subclavian artery. SV, right anterior vena cava. T, rectal 

 diverticulum. XJ, kidney. TJO, ulnar carpal bone. V, pelvis. "W", lung. 

 X, humerus. Y, radius. Z, ulna. ' 



