92 STUDIES OF ANIMAL LIFE. 



3. TADPOLES, A STUDY OF VERTEBRATE METAMOR- 

 PHOSIS. 



].. Arrange and number your specimens according to 

 their ages. 



2. What changes take place during metamorphosis in, — 

 (a) the head ; 



(J) the body ; 



(c) the tail ; 



(<i) the mouth ? 



What is the use of the tail ? 



What becomes of the tail when it disappears ? 



3. Show by means of a sketch the arrangement of the 



muscles and the tail-fin. 



4. Notice in some cases, through the transparent ven- 



tral body wall, the coiled intestine. 

 Why is the intestine in a tadpole so much longer 

 than it is in the frog ? 

 • 5. Does the tadpole eat animal or vegetable food ? 



6. When do the external gills appear and when do 



they disappear ? 



7. Do you find outside traces of gills after the external 



gills have disappeared ? 



8. Which pair of legs develops first ? Why ? 



9. Are the legs well developed before the tail disap- 



pears ? Why ? 

 10. Make drawings to show the process of metamorphosis. 



4. THE STUDY OF A BIRD SKIN. 

 A. In General. 



1. What is the relative size of the head and the body ? 



2. Is a distinct neck present ? 



