114 A GUIDE FOR THE STUDY OF ANIMALS 



c. Lamprey, x \. 



d. Shark: i , head as far as the pectoral fins ; 2, the tail. 



e. Perch, as directed for shark. 



B. Studies of Amphibia 



Progress from Water-living Animals to Land-living 

 Animals 



The Living Frog or Toad 



To show how an Animal may be adapted to both Land and 



Water Life 

 Materials. 



Living frogs in small cages or aquaria; living toads; 

 some pungent liquid, as ammonia. 



Observations. 



The Body. i. Contrast the body of the frog with that 

 of the fish as to regions, shape, and compactness. How 

 do you account for the differences ? 



Locomotion. 2. What kinds of locomotion can a frog 

 use ? Why is it difficult for a frog to crawl or walk 1 

 How far can a frog jump ? How are swimming and 

 jumping accomplished? What do you think is the use 

 of the " hump " on the back ? 



3. Identify in the legs the thigh, shank, ankle, foot, 

 toes, and web, and in the arm, the upper arm, forearm, 

 wrist, hand, and fingers. State in detail the differences in 

 structure and in position between the fore and hind limbs. 

 How do you account for these differences .' 



Feeding. 4. Induce a frog or toad to eat by dangling 

 food, such as a piece of raw meat or meal worms, small 

 earthworms, etc., before it. How does it seize the food ? 



