NATURE-STUDY LESSONS. 47 



14. Examine its mouth to discover whether it has 

 teeth or tongue. 



15. Take two glass jars. Fill each with water from a 

 neighboring pond. Place the same kind of water-plants 

 in each, and in one put some tadpoles. After a time, 

 note the difference of the water in the two jars. 



16. («) Discover what the tadpole eats. Try insects, 



worms, bread, small water-plants, etc. 

 (6) Investigate whether mosquitoes are reduced in 

 numbers by tadpoles and whether they eat 

 vegetable matter. 



17. (a) Describe the changes which gradually take 



place in the tadpole as it develops. 

 (d) Which disappear first the tail or the gills ? 



(c) What becomes of the tail ? 



(d) Which develop first the fore or the hind legs ? 



The passing of an animal from one form or shape to another is called its 

 me/amorpAosis. 



18. Draw tadpoles illustrating various stages in their 

 development. 



19. (a) Place one of the tadpoles on a piece of glass 



with a little water, and examine the gills 

 or a thin part of the tail with a microscope. 

 The flow of the blood can be readily seen. 

 (^) Describe the flow of blood. 



H. Circulation of the Blood. 



20. (a) Procure a thin piece of board as a shingle, cut 



a V-shaped notch in one end, or bore a hole 

 through it near the end and gum a thin, 

 clear plate of mica over the hole. Wrap a 

 frog in a wet cloth, with a leg projecting, 

 and tie it to the board with a part of the 



