232 LABORATORY MANUAL FOR VERTEBRATE ANATOMY 



muscles and membrane should be slit ventrally to meet the transverse incision 

 across the pleuroperitoneum. In this way free access is gained to the para- 

 peritoneal cavity. With the left hand carefully press all of the viscera forward. 

 It is usually necessary to detach the lung from the dorsal wall and push it for- 

 ward also. With the right hand press the pelvic girdle caudad. A space cleared 

 of viscera is thus left dorsal to and in front of the pelvic girdle. Look into this 

 place near the median dorsal line for a somewhat flattened organ, the kidney, 

 situated against the median dorsal wall. The kidney is retroperitoneal, that is, 

 dorsal to the pleuroperitoneum. This latter membrane should be stripped off 

 from the ventral face of the kidney. (In male specimens the rounded yellow 

 testis and black coiled epididymis will be noted attached to the ventral surface 

 of the kidney.) The renal portal vein may now be followed from the point where 

 it leaves the iliac through the pleuroperitoneum toward the kidney. Before 

 reaching the kidney it receives a vein from the carapace. At about the middle 

 of the lateral border of the kidney is a fissure; the renal portal vein enters this 

 fissure and passes onto the ventral face of the kidney where it immediately 

 forks. One of its branches, the vertebral vein, runs forward and may be traced 

 in well-injected specimens by separating the lung from the carapace and raising 

 the lung and also stripping off the pleuroperitoneum from the dorsal wall. The 

 vertebral vein passes anteriorly dorsal to the arches of the ribs and receives 

 laterally an intercostal branch at each suture between the costal plates of the 

 carapace. The intercostal veins anastomose with each other in the curve of 

 the carapace by means of a longitudinal vessel, the margino-coslal vein, which 

 is the anterior continuation of the epigastric vein previously noted. The 

 margino-costal vein also has connections with the abdominal veins. The 

 posterior branch of the renal portal vein passes posteriorly over the ventral 

 face of the kidney and as the internal iliac or hypogastric vein receives branches 

 from the reproductive organs (male), bladder, cloaca, etc. The renal portal 

 vein in its passage along the ventral face of the kidney gives off branches into 

 that organ. The renal portal vein is the posterior part of the posterior cardinal 

 vein (Figs. 55 and 57). The vertebral vein is formed by the longitudinal fusion 

 of segmental branches of the posterior cardinal vein of the embryo. 



Draw these veins as far as you have seen them, adding them to the drawing 

 of the abdominal veins already made. 



The student should consider at this point the differences between the con- 

 nections of the ventral abdominal veins of the turtle and their homologues, the 

 lateral abdominal veins, of elasmobranchs. In the turtle these veins have formed 

 a connection with the renal portal system posteriorly while anteriorly they enter 

 the liver instead of the cardinal system. 



3. The hepatic portal system.— Lift up the lobes of the liver separating them 

 gently from the stomach and duodenum, and find on their dorsal surfaces at the 

 place where the gastro-hepato-duodenal ligament is attached to the liver a large 



