CONTENTS. 



PA9E. 



Article I. — Plankton Studies. [. Methods and Appara- 

 tus in Use in Plankton Investigations at the 

 Biological Experiment Station of the University 

 of Illinois. By C. A. Kopoid (7 Plates.) 

 March, 1897 1 



Article II. — A Contribution to a Knowledge of North 

 American Fresh- water Cyclopidce. By Ernest 

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



Article III. — The North American Species ot: Diaptomus. 

 By Frederick William Schacht. (15 Plates.) 

 December, 1897 97 



Article IV — The North American Centropagidce belong- 

 ing to the Genera Osphranticum, Limnocalanus, 

 and Episehura. By Frederick William 

 Schacht. September, "1898 225 



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

 noisensis, 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 Botifera found in 

 the Illinois River and Adjacent Lakes at Havana, 

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

 uary, 1899 301 



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



Coccidce. By T. D. A. Cockerell. February,! 899. 389 



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



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



Article IX — Plankton Studies. III. On Plalydorina, a 

 New Genus of the Family Volvocidai, from the 

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

 foid (1 Plate.) December, 1899 419 



Article X. — Notes on Species of North American Oligo- 

 chmta. III. List of Species found in Illinois, 

 and Descriptions of Illinois Tabificidcp, By 

 Frank Smith. (2 Plates ) March. 1900 ". 441 



Article XI — Notes on Species of North American Oligo- 

 chceta. IV. On a New Lumbriculid Genus from 

 Florida, with additional Notes on the Nephridial 

 and Circulatory Systems of Me sopor odrilus asym- 

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

 June, 1900 459 



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



Moore. (8 Plates.) February, 1901 479 



