FROG. 101 



2. Observe the contractions of the heart. Note 



the order of sequence of the contraction 

 in the four parts of the heart. The heart of 

 lower vertebrates often continues to beat 

 after the death of the animal. 



3. The veins. 



A. The Anterior Abdominal Vein and its Trib- 



utaries. 



(a) Trace the course of the anterior abdominal 



vein into the liver. Just before its en- 

 trance it divides into two branches, one 

 going to each main lobe of the liver. 



(b) Trace it posteriorly. It is formed by the 



union of two pelvic veins which are 

 ventral branches of the femoral veins. 



(c) Trace the pelvic vein of one side back to 



the femoral from which it arises. 



(d) Follow the femoral vein posteriorly, to 



see from what region it is bringing 

 blood. 



B. The Kenal Portal System. 



(a) The dorsal branch of the femoral vein is 

 the renal portal vein. It receives the 

 sciatic vein and small veins from the 

 body-wall, etc. The renal portal vein 

 passes forward to the outer side of the 

 kidney and enters that organ by means 

 of numerous branches. 



C. The Hepatic Portal System. 



