80 STUDIES OP ANIMAL LIFE. 



6. What are the principal fishing grounds in North 



America ? 



7. What are the most common food fishes found in the 



fish markets of your neighborhood ? Where do 

 they come from ? 



8. What is the United States Fish Commission ? 



9. What are the advantages of the backbone plan of 



structure ? 



2. THE FROG. 



A. Habitat. 



1. What is the habitat of the frog? 



B. General Observations. 



1. How is the shape of the frog adapted to its two 



methods of locomotion, jumping and swimming ? 



2. How is the frog's color adapted to conceal the frog ? 



Are the black spots a help or a hindrance ? 



3. What is the arrangement of the black pigment spots 



on the back? On the hind legs when they are 

 folded ? 



4. Observe the " hump " on the back. 



5. Observe the looseness and moist condition of the 



skin. 



6. Is there any exoskeleton ? 



7. Where are the frog's " croaking sacs " ? (They are 



not always present.) 



8. What is the resting position of a live frog ? 

 What advantage is there in this position? 



C. The Head. 



1. What is its shape ? 



2. Is there a neck ? What is a " neck " ? 



3. The Eyes. 



