v.^^,^^^ /^ 7^ 



STATE OP 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 BY AUTHORITY OF THE STATE OF ILLINOIS 



URBANA, ILLINOIS 

 November, 1925 



