A TURTLE 153 



Follow the course of the abdominal veins and their branches. 

 At a point opposite the heart they leave the peritoneum and pass 

 dorsally (inward) to the liver; this will hardly be seen at present, 

 on account of the opacity of the peritoneum. At the angle where 

 this turn is made, each abdominal vein receives an anterior vein 

 from the pectoral muscles. With forceps pull these muscles loose 

 from those beneath and trace the further course of this vein and 

 its branches. It will be seen to come from the outer side of the 

 pectoral girdle. 



Pressing aside or removing (if necessary) the pelvic muscles, 

 study the distribution of the posterior branches of the abdominal 

 vein and the renal portal system. The vein will be seen to turn 

 laterally near the anterior border of the pelvis and to pass along 

 or just beneath this border toward the hind leg. Not far from the 

 turn, it receives a branch which may be traced backward over the 

 pelvis, near the hinder border of which it is joined by a vein con- 

 necting it with the corresponding vein on the opposite side of the 

 body. Trace its further course. 



Return now to the main vein and trace it to the muscles which 

 join the leg with the inner surface of the carapace, lifting up the 

 pelvis and its muscles and separating them from the peritoneum 

 beneath. Cut the skin where it joins the carapace around the 

 hinder end of the animal, lift it up, and, without cutting anything, 

 separate the muscles and other tissues beneath it, until the large 

 veins are seen. The abdominal vein may be traced in this manner 

 to its origin, and will be seen to be formed by the union of three 

 large veins,— the femoral vein from the leg, the caudal vein from 

 the tail, and the renal portal vein which passes dorsally to the kid- 

 ney. Trace the renal portal vein medially to the kidney, and the 

 other two veins as far as possible. 



With sharp scissors cut away the entire ventral portion of the 

 peritoneum, leaving, however, the abdominal veins intact. Ob- 

 serve the anterior ends of these veins where they pass dorsally and 

 enter the liver. 



Exercise 30, Draw a diagram showing the abdominal veins, their 

 anterior and posterior branches, and the renal portal system, so 

 far as observed. 



