Walks with the Children. 161 



II. The Crayfish. 



Its color, size, shape. Two sets of legs, five pairs of 

 large true legs, and five pairs of false ones. Two pairs of 

 horns (antennae). How does the first pair differ from the 

 others? How do the first three pairs differ from the 

 others ? What shape is the tail ? Fan. Describe the eyes. 

 How does the crayfish move ? 



After studying the crayfish alive add a little salt or vine- 

 gar to the water to kill it. When killed, remove from the 

 water and spread it out on a piece of wood and dry it. It 

 may be glued to a block and varnished,, and become an in- 

 teresting specimen in the museum. 



If near the seaside, lobsters, crabs, and shrimps may also be 

 collected and studied in the same way, but these larger ones 

 should be cured with glycerine, alcohol, or corrosive subli- 

 mate to keep them. 



Tell the children how these strange creatures may lose a 

 leg, or any single part, and another will grow in its place. 

 Examine the eyes with a microscope and show them the 

 many parts each possesses. 



III. Prog's ggs. 



Study their form, size, and color. Get the children to 

 discover that the eggs are laid in chains or strings of white, 

 having the yolks scattered along at regular distances. 



Put the eggs in a glass vessel and have pupils record ob- 

 servations from time to time. Interest will reach the pitch 

 of enthusiasm when the tadpoles begin to hatch. 



As the weeks roll along the date of each stage of devel- 

 opment should be noted and recorded, so that when the 

 perfect frog is developed the time since the eggs were found 

 should be known. 



This is real scientific work, and these observations are of 

 incalculable value to the child and to the teacher. 



Procure a large number of bottles, with wide mouths, 

 getting as clear glass as possible. Place some of the eggs 

 in one, add alcohol or dilute glycerine and label it No. i. 



