TWO YOUNG NATURALISTS. 219 



"In the seas, there is another class of creatures 

 scarcely less numerous and ubiquitous, though often 

 of somewhat larger bulk, that form as it were a sort 

 of complement to the diatoms : the Foraminifera, 

 whose forms are varied almost to infinity, are found 

 in large accumulations on the floors of the ocean, and 

 their skeleton is pierced in all directions by little 



FRESHWATER HYDRA. 



holes, from which project great numbers of vibratile 

 ciliae. Thus, besides infinitely small diatoms, there 

 are other infinitely small beings, and these also help 

 to make up the structure of worlds." 



To assist him in his microscopic work, Leon had 

 established in a glass globe a sort of small artificial 

 pond with some mud, several plants and insects, and 

 on its surface some pieces of duckweed. Tired of 



