THE EARTHWORM 103 



g. Examine a "head" of clover, with the magnifying glass if 

 possible; of what is the head composed? Remove an in- 

 dividual blossom by cutting it off at its point of attachment. 

 Take the blossom to pieces, and describe the flower parts in 

 detail. Which part of the clover head matures first, the outer 

 or the inner part? 



h. Study the dandelion. Note that it is made up of many 

 flowers growing on the same receptacle. Describe the corolla 

 of each flower. Describe the stamens and pistil. 



Examine a dandelion that has gone to seed. Remove the 

 winged seeds (akenes), and describe one of them. Make a 

 drawing of one. Draw the receptacle that remains. Describe 

 the double circle of green "leaves" below the receptacle; are 

 they true leaves? Are they sepals? 



EXERCISE 95 

 THE EARTHWORM 



Materials. Earthworm and leech. 



a. Read 336 of the text. Put an earthworm on a moist sheet 

 of paper (newspaper), or on some moist earth, and find out how 

 it crawls along. Which is the anterior (head) end? Does the 

 worm crawl forward or backward? While it is moving, touch 

 the part that is forward; does the worm reverse its direction? 



Count the number of segments in the earthworm. Count 

 the number in several specimens, if possible. Do all have the 

 same number? 



b. Look carefully at the worm while it is at rest. Can you 

 see any pulsations, or "beats," that pass through the body? 

 What are these? Is the body wall of the worm thick or thin? 

 Do any of the internal organs show through the body wall? 



c. Does the earthworm require air for its respiration? Why 

 are so many worms found on the ground and sidewalks after 



