XVI. THE FISH AND FROG, AN INTRODUCTORY 

 STUDY OF VERTEBRATES 



Problems. — To determine how a fish and a frog are fitted for 

 the life they lead. 



To determine some methods of development in vertebrate 

 animals. 



(a) Fishes. 



(&) Frogs. 



(o) Other animals. 



Laboratoht Suggestions 



Laboratory exercise. — Study of a living fish — adaptations for protec- 

 tion, locomotion, food getting, etc. 



Laboratory demonstration. — The development of the fish or frog egg. 



Visit to the aquarium. — Study of adaptations, economic uses of fishes, 

 artificial propagation of fishes. 



To THE Teacher. — This chapter is intended to introduce the student to the 

 life history, structure, and adaptations found in a vertebrate, the fish or frog. If 

 time permits, both forms may be used, but the writer has found that for use in the 

 early spring (which would be the logical time for this exercise if the course was be- 

 gun in the fall) the frog is a more useful form because of its superficial similarity to 

 the structure of man and because of the ease with which developmental material 

 may be obtained. 



The fish, however, as a living specimen for laboratory use is excellent, espe- 

 cially for the study of adaptations. The concept of a structural adaptation is ex- 

 tremely difficult for a pupil beginning, and considerable drill should be given in an 

 attempt to fasten the concept. Field or aquarium trips may be made to form an 

 important part of this work, thus adding interest through varied work. 



Problem 133 : To determine how alive fish is fitted for life. 

 Materials. — Small battery jar with small living fish such as 

 goldfish, bream, or minnows. 



a. Locomotion 

 Observations. — Note adaptations for locomotion. How is the 

 body of the fish fitted for life in the water? Mention three dif- 



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