72 STUDIES OF ANIMAL TYPES 



A. STUDY OF A LIVING FROG. Put a live frog in a large 

 tub or in an aquarium and watch it swim. What legs are 

 used in swimming? Watch the movements of these legs. 

 Do the front legs perform any active function in swimming ? 

 What position does the frog assume when it is quietly rest- 

 ing ? Where does it rest ? How long can it stay below 

 the surface ? How are the hind legs held when it is quiet ? 

 Why is the head held out of the water ? Find the nostrils 

 near the tip of the nose, one on each side. Notice the sort 

 of rhythmic movements of the openings to the nostrils. 



Put some wire netting over the tub and imprison living 

 house flies beneath it. Determine, if possible, how the 

 frog eats. 



Put the frog on the floor for a little time and observe its 

 method of locomotion under these conditions. 



Determine how this animal breathes. Observe the 

 nostrils, mouth, and abdomen, and describe the movements 

 of each. 



Make a drawing of a living frog in its sitting posture. 



B. EXTERNAL FEATURES. Note the short, wide, hump- 

 backed body with the triangular head. Note the absence 

 of fins, neck, and tail. How do these features compare with 

 a fish? 



How do the hind legs of the frog compare with the front 

 ones ? How many toes on the hind and on the front feet ? 

 What is found between the hind toes ? Note that each leg 

 has three parts. The front leg is divided into arm, fore- 

 arm, and hand; the hind leg into thigh, shank, and foot. 



Make a drawing of a front and hind leg showing the parts. 



Note the smooth, moist, scaleless skin and the markings 

 on the body and legs. What color is the frog above? 

 What color is it below? The color above usually accords 



