STATE OF ILLINOIS 
DEPARTMENT OF REGISTRATION AND EDUCATION 
DIVISION OF THE 
NATURAL HISTORY SURVEY 
STEPHEN A. FORBES, Chief 
Vol. XIV. BULLETIN Article IV. 
Changes in the Bottom and Shore Fauna of 
the Middle Illinois River and its Con- 
necting Lakes since 1913—1915 as a 
Result of the Increase, South- 
ward, of Sewage Pollution 
BY 
ROBERT E. RICHARDSON 
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PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS 
URBANA, ILLINOIS 
December, 1921 
