Article VI. — A List of the Protozoa and Rotifera found in 

 the Illinois River and Adjacent Lakes at Havana, III.* 

 By Adolph Hempel. 



INTRODUCTORY. 



The material studied in the preparation of this paper was 

 collected at the Biological Experiment Station established on 

 the Illinois River, at Havana, April 1, 1894, by the Univer- 

 sity of Illinois and the Illinois State Laboratory of Natural 

 History. The work of collecting the material began April 

 7, 1894, and was carried on almost entirely at nine substa- 

 tions, designated as A, B, C, D, E, F, G, K, and L. The 

 first three are in Quiver Lake, which is an arm of the river 

 on its east side, about two miles above Havana. A is at the 

 head of the lake ; B, at a wet, springy place on the eastern 

 shore, about half a mile from the head ; and C, about a mile 

 and a half from the head, including both the east and west 

 shores at this point as well as the middle of the lake, where 

 the towing-net was hauled, the depth here at low water being 

 about four feet. D is about half a mile above Havana, on the 

 east bank of the river, and E about two and a half miles north 

 of the town, in the main river, opposite C, collections being 

 taken especially from the west shore and the middle of the 

 river, where the depth at low water was about nine feet. About 



*I3efore Mr. Hernpel had completed that part of his manuscript relating to the 

 Protozoa, he left to accept a position in the Muse t Paulista, in Sao Paulo, Brazil, and 

 the entire manuscript was placed in my hands by Dr. Forbes to be prepared for pub- 

 lication. At first I was reluctant to undertake the work, but realizing the value of 

 the paper as planned by Mr. Hernpel to students and teachers of Illinois natural 

 history, I have spared no effort to put it in the most useful form for this class of 

 workers. 



On account of the limited time and area represented in this list, it can only be 

 regarded as a preliminary one, not sufficient for permanent generalizations on sea- 

 sonal or local distribution, but rather as a history of these groups at the Station 

 during the two years covered by Mr. Hempel's work. It seemed undesirable, for (he 

 same reason, to attempt to give keys to the species listed. I have, however, for the 

 Protozoa, carefully compiled from Butschli a synopsis of the distinctive characters of 

 the larger subdivisions represented in the list, and have drawn up from Butschli, 

 Leidv, and Kent condensed generic descriptions, following, as did Mr. Hernpel, the 

 order given by Butschli. The chlorophyll-bearing forms, such as Volvox and Euglena, 

 are retained among the Protozoa since they are included by Biitschli, but it is proper 

 to state that they are now regarded as plants by :i large number of authors. For the 

 Rotifera.l have compiled a synopsis of the families from Hudson and (fosse, and 

 Mr.IIempers generic diagnoses are mostly from the same source. 



Under each species in the list is a brief account of the important points in its 

 history for the two vears. These accounts were drawn up from Mr. Hempel's records, 

 and may prove of especial value to students at the Station. Aside from these sum- 

 maries and the additions previously mentioned, the manuscript remains substantially 

 as Mr. Hempel left it, and will be found to contain much interesting and useful 

 information for the student of microscopic life. CHAS. A. HART. 



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