Vol. 5 No. 1-12 (1901)
Article 1- Plankton Studies. I. Methods and Apparatus in Use In Plankton Investigations at the Biological Experiment Station of the University of Illinois. C. A. Kofoid
Article 2 - A Contribution to a Knowledge of North American Fresh-Water Cyclopidae. Ernest B. Forbes
Article 3 - The North American Species of Diaptomus. Frederick William Schacht
Article 4 - The North American Centropagidae Belonging to the Genera Osphranticum, Limnocalanus, and Epischura. Frederick William Schacht
Article 5 - Plankton Studies. II. On Pleodorina Illinoisensis, a New Species from the Plankton of the Illinois River. C. A. Kofoid
Article 6 - A List of the Protozoa and Rotifera Found in the Illinois River and Adjacent Lakes at Havana, Ill. Adolph Hempel
Article 7 - First Supplement to the Check-list of the Coccidae. T. D. A. Cockerell
Article 8 - A Statistical Study of the Parasites of the Unionidae. H. M. Kelly
Article 9 - Plankton Studies. III. On Platydorina, a New Genus of the Family Volvocidae, from the Plankton of the Illinois River. C. A. Kofoid
Article 10 - Notes on Species of North American Oligochaeta. III. List of Species found in Illinois, and Descriptions of Illinois Tubificidae. Frank Smith
Article 11 - Notes on Species of North American Oligochaeta. IV. On a New Lumbriculid Genus from Florida, with Additional Notes on the Nephridial and Circulatory Systems of Mesoporodrilus Asymmetricus Smith. Frank Smith
Article 12 - The Hirudinea of Illinois. J. Percy Moore