BULLETIN 



Illinois 3 tate Laboratory 



NATURAL HISTORY, 



Urbana, Illinois 



VOLUME V. 



ARTICLE I.— PLANKTON STUDIES. I. METHODS AND 

 APPARATUS IN USE IN PLANKTON INVESTIGA- 

 TIONS AT THE BIOLOGICAL EXPERIMENT STA- 

 TION OE THE UNIVERSITY OF I ILL NO LS. 



By C. A. KOFOID, Ph. D. 



Illinois State Laboratory of Natural History, 



I'RHANA, ILLINOIS. 



1897. 



