f 16 A NURSERY FOR THE MICROSCOPE. 



for examination in his glass tank. As a rule, 

 however, the lower vegetable forms thrive better in 



Fig. 71. 



%?&, 



mvm c c c -^5," 



* K i.z 



Cosmarium margaritiferuni 

 X 250. 



Fig. 72. 



Fig. 73- 



Micrasterias rotata 

 X 250. 



Closterium slriolatum x 250. 



small tanks than in large ones. The desmids are 

 purely fresh-water algae, and may readily be dis- 

 tinguished from the diatoms to which they are so 



