THE TURTLE. 103 



3. A thin membrane covers the internal organs ; through 

 it the heart may be seen beating. Cautiously avoid- 

 ing blood-vessels, cut away this thin covering, and 

 distinguish the following parts of the heart: 



a. The large, hinder part, the ventricle. 



b. In front, on each side, the two auricles. 



c. Between the auricles are blood-vessels, branching 

 toward the head. As in the frog, there are two 

 aortae, the right and left, which unite posteriorly. 



4. Make out the following order of the heart's beat : 



a. The contraction of the blood-vessels leading to the 

 auricles. 



b. The contraction of the auricles. 



c. The contraction of the ventricle. 



5. On each side of the heart appears the dark liver, con- 

 sisting of two main lobes, connected by a cross-band. 

 Search the liver to find the bile-sac. 



6. Under the left lobe of the liver is the stomach. 



7. From the stomach trace the intestine to the trans- 

 verse vent under the tail. 



8. Masses of eggs may be found in the ovary (if a 

 female). 



9. Find a large bladder near the pelvis. 



10. Raise the liver to find the lungs; pull forward the 

 neck, find the windpipe, and insert a blowpipe. By 

 inflating, the lungs may be better seen. When the 

 lungs are fully inflated, tie a string tightly around 

 the windpipe ; carefully remove the lungs, and hang 

 them up to dry. When they are thoroughly dry and 

 firm, cut them across, and compare with the lungs of 

 the frog and rabbit. 



