VBETEBRATA. 91 



b. Tibia-fibula, the bone of the shank. Why is its 



name double ? 



c. Tarsals, the bones of the ankle. (Compare with 



the wrist and the human ankle.) 

 Why is the frog's " ankle " so long ? 



d. Metatarsals, the bones of the instep. 



e. Phalanges, the bones of the toes. How many 



bones in each toe ? Why are they so long ? 

 What difference in structure makes possible in 

 the live frog's leg a greater range of movement 

 than in the arm ? 

 9. Drawings. 



O. Suggestive Questions. 



1. Where is the frog in winter ? 



2. Does a frog breathe during hibernation ? 



3. Does a frog need food during hibernation ? Why ? 



4. Where are the eggs of the frog deposited ? At what 



time of the year ? 



5. Are the dark pigment spots exactly alike on all frogs ? 



6. Are the spots alike in the same frog at different sea- 



sons of the year ? 



7. Can a frog walk, run or float ? 



8. Are frogs of any economic importance ? 



9. What is the frog's protection from its enemies ? 



10. Make a diagram of a transverse section of the frog 



to show the relation of the neural cavity, spinal 

 nerve cord, body cavity, alimentary canal and the 

 body wall to each other. 



11. Make a similar diagram of the transverse section of 



an earthworm showing the relation of the body 

 cavity, alimentary canal, nerve cord and body wall 

 to each other. 



