56 LABORATORY WORK. 



How many lobes are there in the liver? Are they sym- 

 metrically placed? Beside the portal vein and the hepatic 

 artery is the bile-duct. Trace it forward and see how its 

 branches arise from the liver-lobes. Trace it backwards 

 and see where it enters the intestine. Look on the posterior 

 surface of liver for the gall-bladder. Tip the liver towards 

 the tail. See how it is attached by mesenteries to a 

 muscular partition (diaphragm) bounding the peritoneal 

 cavity in front. See the oesophagus and a blood-vessel 

 (postcava) extending from the liver through the dia- 

 phragm. Sketch the alimentary canal. 



Cut through the oesophagus just in front of the stomach 

 and through the rectal portion of the intestine, and cutting 

 the mesentery close to the intestine remove the alimentary 

 canal. 



In the body-cavity see, dorsal to the liver, the kidneys. 

 Are they at the same level? Covering the anterior end of 

 each kidney is a triangular supra-renal capsule. Trace 

 from each kidney (median surface) backwards a whitish 

 tube, the ureter. In the median line of the body-cavity is 

 the aorta already mentioned. -Trace it backwards, finding 

 the arteries (renal) going to the kidneys. Farther back 

 the aorta divides into a pair of common iliac arteries. 

 Trace these into the legs. Do you find them to divide? 



Just behind the point of division of the aorta into the 

 common iliacs can be seen the common iliac veins, which 

 return from the legs and unite into a vessel, the postcava, 

 which passes forward, at first dorsal to the aorta. A little 

 farther forward the postcava receives an ileo-lumbar vein 

 from each side, and then a renal vein from each kidney. 

 From the kidneys trace the postcava forward through the 

 liver. This may readily be done by cutting away the ven- 

 tral part of the liver and then, inserting the point of the 



