36 A FIELD GUIDE IN NATURE-STUDY 



magnifier to watch all the changes. Record the observations somewhat 

 as follows: 

 April 1 6 



7 : 10 A.M. Eggs are divided into two parts and the line begins to show dividing 



each of these parts again. 

 7:45 A.M. Eggs are now four-celled (drawing). 

 8:10 A.M. I can see a new line of division coming in nearly around the middle 



(drawing), etc. 



Keep the record as complete as you can, recording the important events 

 in the whole life-history of the frog or toad. 



When you find the eggs in the pond they are imbedded in a mass of 

 jelly. Of what use is this ? Which side of the egg is uppermost, the black 

 or the white? Can you see that this is any advantage? It may help 

 you to think this out if you recall the color of the pond bottom. Recall 

 also the color of the clothing you prefer to wear in summer. By what 

 means do we usually hatch eggs ? 



Tadpoles. When the tadpoles hatch out, where do they go and what 

 do they do ? When they begin to feed, what do they eat ? How do they 

 eat? How do they breathe? Are they "fish" or frogs now? Keep a 

 few of them and try to rear them. Secure also some large tadpoles from 

 the ponds and put them in an aquarium at one end of which is a bank of 

 sand above the surface of the water, so the young frogs may crawl out on 

 the land. Watch to see the legs develop and the tail disappear. They 

 must now be fed on insects. By what means are they now breathing 



Turtles. Among the commonest turtles are the following (learn to 

 know these at least) : the western painted pond, the snapper, the geographic, 

 the spotted, the soft-shell, the box. See the museum specimen of the 

 turtle's skeleton. What really is its shell ? 



Fish. There are a number of wonderfully brilliant and interesting 

 small fish in our streams. These may be kept in schoolroom aquaria and 

 are very attractive. Learn to know the pumpkin seed, blue gill, red- 

 bellied dace, common shiner, brook silversides, chub, mud minnow, and 

 rainbow darter. 



Aquarium. A school aquarium is easily made as follows: Obtain nine 

 lineal feet of half-inch angle tin from a tinsmith. Cut this and solder to- 

 gether so as to make a frame 6| by 8J by 10 inches with the open side of the 

 angles of the tin turned in. Obtain one piece of 8 by 10 window glass, 

 2 pieces 6 by 10 and two pieces 6 by 8. These may be cut of old window 

 glass with a wheel glass-cutter. Make a cupful of cement with 8 oz. of 

 whiting, i of litharge, and i of red lead. Mix these dry, then add some 

 raw linseed oil, stirring it in with a putty-knife. When very stiff take it 



