170 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



being designated the gastros picnic ligament. The lung is also attached to th 

 mesogaster by a short mesentery. That part of the dorsal mesentery supportin 

 the small intestine is the mesentery, in the limited sense; that part supportin 

 the large intestine is the mesorectum. 



The ventral mesentery is present only in the region of the liver and urinar; 

 bladder. One part of it forms the long mesentery extending between the medial 

 ventral line of the body wall and the median line of the ventral face of the live: 

 This is the falciform ligament of the liver. It contains a number of blood vessel 

 which pass from the ventral body wall into the substance of the liver (wrier 

 they join the hepatic portal vein) . In the free posterior margin of the falciforn 

 ligament the ventral abdominal vein crosses from the body wall to the liver 

 On raising the liver the gastrohepatic ligament will be seen extending from th 

 anterior part of the stomach to the dorsal face of the liver. In the region of thi 

 pancreas the hepatoduodenal ligament joins the duodenum and liver and inclose; 

 the greater part of the pancreas. The tails of the pancreas, however, are sit 

 uated in the mesentery of the small intestine. Both of the ligaments jus' 

 mentioned are parts of the ventral mesentery. The last part of this mesenten 

 is found extending from the urinary bladder to the mid ventral line of the bod} 

 wall; this is the median ligament of the bladder. 



Each gonad has a mesentery: mesovarium in the female, mesorchium in th< 

 male. The mesentery of the oviduct is the mesotubarium. These should b< 

 located by lifting up the structures in question. 



The falciform ligament should now be severed without, however, cuttinj 

 through the ventral abdominal vein. The numerous lobes of the liver appearing 

 as scallops of the margin may now be seen more clearly. On raising the righ 

 side of the liver, the right lung may be identified dorsal to it. Is it of the sami 

 length as the left lung ? The small gall bladder will be seen on the dorsal surfaci 

 of the right side of the liver. Its ducts surrounded by pancreas tissue may bi 

 readily traced to the duodenum. The pancreas is said to open into the duode 

 num by a number of fine ducts. 



The anterior end of the pleuroperitoneal cavity is closed by a membrane 

 the transverse septum. The liver is attached to this by the coronary ligament 

 which is continuous posteriorly with the falciform ligament. The mode of forma 

 tion of the septum and the coronary ligament was described in connection witl 

 the dogfish. 



3. The pericardial cavity. — Make a median ventral incision through th 

 skin from the level of the fore limbs forward to the level of the gills. Remov 

 the underlying muscles bit by bit until you have exposed a membrane, th 

 parietal pericardium. Cut through this, membrane. The pericardial cavity ii 

 which the heart is situated is thus exposed. Widen the opening into the cavit; 

 by cutting laterally along the anterior margin of the pectoral girdle. Th 

 muscles between the pericardial cavity and the fore limbs may also be split 



