16 NATURE-STUDY LESSONS. 



20. How many bones are there in each finger ? How 

 many in the thumb ? 



21. In respect to the number of bones, compare the 

 thumb and fingers with the great toe and small toes 

 respectively. 



22. (a) Shut the hand or grasp a small, round stick 



and observe the position of the thumb and 



fingers. 

 (^) Note how the hand is adapted to the work of 



grasping. 

 (c) How would the power of grasping be affected 



by each finger having only one bone? 



23. Describe the joints where the fingers are attached 

 to the large part of the hand. 



These joints are called knuckles. 



24. {a) Compare the size of the bone at the joint with 



its size near the middle. 

 ip) Discover the advantage of the enlargement of 

 the bone at the joint. 



25. In how many directions can you move the fingers 

 at the knuckles ? 



26. Observe in what directions you can move the parts 

 of the fingers beyond each of the joints. 



27. Infer the advantage in the difference of movements 

 of the joints. 



28. Name other joints in the body that have the same 

 movement as the knuckles. 



29. Name other joints in the body similar in move- 

 ment to those of the fingers. 



