STATE OF ILLINOIS 

 DEPARTMENT OF REGISTRATION AND EDUCATION 



DIVISION OF THE 

 NATURAL HISTORY SURVEY 



STEPHEN A. FORBES, Chief 



Vol. XV. 



BULLETIN Article IX. 



The Lake as a Microcosm 



BY 



STEPHEN A. FORBES 



PRINTED BV AUTHORITY OF THE STATE OF ILLINOIS 



URBANA, ILLINOIS 



November, 192s 



