No. 1. — Contributions to the Morphology of the Turbellaria. 
IL 
On some Turbellaria from Illinois! By W. MoM. Woopwortn. 
Tam material upon which this paper is based was collected by the 
staff of the Biological Experiment Station of the Illinois State Labora- 
tory of Natural History at Havana, Illinois, and came from the Illinois 
River and the streams and lakes tributary to it.” The material was 
collected between the first of July and the last of October, 1894, and 
the first of March and the last of September, 1895. I am indebted to 
Prof. S. A. Forbes, Director of the Illinois State Laboratory, for the 
privilege of studying the collections, and am under obligations to Dr, 
C. A. Kofoid, Superintendent of the Experiment Station, and to Prof, 
Frank Smith for their patience and kindness in answering my many 
inquiries, and for sending me living material from time to time. I must 
thank these gentlemen also for the excellent state of preservation of all 
the material that came into my hands. 
Although I have to report but two species that are probably new, it is 
hoped that these pages will help to clear away some of the confusion 
that exists in the published accounts of the North American fresh-water 
Turbellaria, Although the figures accompanying this paper do not, with 
two exceptions, represent new forms, they are, I believe, the first pub- 
lished illustrations, in the natural colors of the living animals, of some 
of our common fresh-water Turbellaria. 
I have not entered into the finer anatomy of the species to any extent, 
as that would have been beyond the scope of the paper. Unfortunately, 
too, not all of the species were represented by sexually mature indi- 
viduals, and as the characters of the sexual organs are of the highest 
systematic importance, the unavoidable lack of data upon this subject 
must necessarily leave my work more or less incomplete. It is to be 
1 Contributions from the Zoólogical Laboratory of the Museum of Comparative 
Zoölogy at Harvard College, E. L. Mark, Director, No. LX XXIII. 
2 For a description of the localities under investigation by the Experiment 
Station, see ©. A. Hart, On the Entomology of the Illinois River ind adjacent 
Waters. Bull. Ill. State Lab. Nat, Hist., Vol. IV. p. 150, 1895, 
VOL. XXXI. — NO. 1. 1 ` 
