174 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



Press both lobes of the liver forward against the pectoral girdle and look on 

 the dorsal surface of the liver. The elongated stomach will be found curving 

 dorsal to the lateral border of the left liver lobe. On following the stomach 

 anteriorly, the narrow esophagus will be found entering the stomach. The 

 stomach passes along the dorsal surface of the left lobe of the liver to the middle 

 of which it is attached along its entire length by the short gastrohepatic ligament. 

 About opposite the bridge connecting the two lobes of the liver, the stomach 

 passes insensibly into the small intestine, the first part of which is the duodenum. 

 The duodenum is united to the middle of the dorsal surface of the right lobe 

 of the liver by the hepatoduodenal ligament. In this ligament is situated a long 

 white gland, the pancreas. About one-quarter of an inch back of the right end 

 of the pancreas, a pancreatic duct passes from the pancreas into the duodenum 

 and may be revealed by picking away the substance of the pancreas at 

 this point. On the dorsal surface of the right lobe of the liver near its lat- 

 eral border is the large gall bladder, which is connected to the duodenum by a 

 short but stout bile duct. Beyond the entrance of the bile duct the small 

 intestine turns sharply posteriorly and is then thrown into a number of coils. 

 In the case of female specimens it will generally be necessary to remove one of 

 the large egg-bearing ovaries at this point before the intestine can be conveniently 

 traced farther. By lifting the coils of the small intestine note the dorsal mesentery 

 which attaches it to the median dorsal line of the coelom; this part of the dorsal 

 mesentery is the mesentery proper. Follow the dorsal mesentery forward and 

 note the portions of it which support the duodenum and the stomach, named 

 mesoduodenum and mesogaster, respectively. The mesoduodenum is fused to the 

 hepatoduodenal ligament so that the two appear as one, but the mesogaster is 

 distinct from the gastrohepatic ligament. Trace the small intestine posteriorly, 

 noting the coiling of the mesentery corresponding to the coils of the intestine. 

 Find on the right side the entrance of the small intestine into the large intestine 

 or colon. At the junction of the small and large intestine is a slight projection, 

 the caecum. The colon generally crosses the pleuroperitoneal cavity transversely 

 and then turns posteriorly and runs straight caudad to the cloaca. Note the 

 mesocolon supporting the colon. In the transverse part of the colon it is fused 

 to the mesogaster. In the mesocolon on the dorsal side of the colon shortly 

 beyond the caecum is a rounded red body, the spleen. Trace the colon to the 

 place where it disappears dorsal to the pelvic girdle. At this point ventral to 

 the colon will be found the large, thin-walled, bilobed urinary bladder. It is 

 generally greatly distended with urine but in some specimens may be contracted 

 to a small mass. The bladder has no ligaments, the peritoneum leaving the 

 body wall around the stalk of the bladder and passing over its surface to form 

 its visceral investment. 



Cut away the pelvic girdle by making a cut through each side of it with the 

 bone scissors and removing a median piece. The large intestine will be traced into 



