^^« 24 f909 



CONTENTS. 



PAGE. 



Article I. — [^lankton Studies. I. Methods and Appara- 

 tus in Use in Plankton Investigations at the 

 Biological Experiment Station of the University 

 of Illinois. Bj C. A. Kofoid (7 Plates.) 

 March, 1897...." 1 



Article II. — A Contribution to a Knowledge of North 

 American Fresh- water Ci/clopida'. By Ernest 

 B. Forbes. (13 Plates. ) September, 1897 27 



Article III. — The North American Species ot Diapfouius. 

 By Frederick William Schacht. (15 Plates.) 

 December, 1897 97 



Article IV — The North American Centropag id (eheXong- 

 ing to the Genera O^pJnrntticum, Lintnocahtnns, 

 and EpificJiufd. By Frederick William 

 Schacht. September, 1898 225 



Article V. — Plankton Studies. II. On Pleodorintt illi- 

 noheush^ a New Species from the Plankton of 

 the Illinois River. By C. A. Kofoid. (12 

 Plates. ) September, 1898 273 



Article VI — A List of the Protozoa and Bofifera found in 

 the Illinois River and Adjacent Lakes at Havana. 

 Illinois. By Adolph Hempel. (5 Figures.) .lan- 

 uary, 1899 301 



Article VII. — First Supplement to the Check-List of the 



Corcidcc. ByT.D. A. CocKERELL. February, 1899. 389 



Article VIII. — A Statistical Study of the Parnsites of the 



Unionidw. By H. M. Kelly. May, 1899 399 



Article IX — Plankton Studies. III. On Plalndor'nia, a 

 New Genus of the Family Volvocidce, from the 

 Plankton of the Illinois River. By C. A. Ko- 

 foid. ( I Plat i. ) December, 1899 419 



Article X. — Notes on Species of North American O/igo- 

 clnffa. III. List f Species found in Illinois, 

 and Descriptions of Illinois Tidjifiridcr Bv 

 Frank Smith. (2 ",ates ) March, 19(0 '.441 



Article XI —Notes on Species of North American Oligo- ■ 

 cliccfa. 1 V. On a New Lumbriculid Genus from 

 Florida, with additional Notes on the Nephridial 

 and Circulatory Systems of Mfsoporodrihis nsi/m- 

 nietricHS Smith. By Frank Smith. (1 Plate.) 

 June, 1900 459 



Article XII. — The Hirudinea of Illinois. By J Percy 



Moore. (8 Plates. ) February, 1901 479 



