16 



ETON NATURE-STUDY 



An equable temperature must be maintained if possible. Washed 

 sand and gravel should cover the bottom, and two or three large 

 flints set up against one another will form a hiding-place. Direct 

 sunlight should be screened from at least half of the aquarium. 



FIGURE. 153 A Terrarium with accommodation for 

 amphibious animals. 



Several kinds of water plants will serve as aerators of the water, 

 crow-foot, goose-weed, and duck-weed being hardy and easily grown. 

 In aquaria supplied with running water the vallisneria plant will 

 flourish, but not otherwise. There are many excellent handbooks 

 as to the management of aquaria, and their most profitable denizens, 



