Date of this Version
Thesis (Ph.D.)--University of Illinois, 1911.
Illinois Biological Monographs (July-October 1914) volume 1, numbers 1 and 2.
Contributions from the Zoological Laboratory of the University of Illinois (1914) number 33.
Several years ago while studying under Professor Henry B. Ward .at the University of Nebraska the writer began an investigation of a cestode parasitic in Amblystoma tigrinum (Green). That investigation resulted in a paper (La Rue 1909) in which a number of points in the anatomy of Proteocephalids were cleared up and certain problems were -outlined for investigation at an early date. In the meantime the writer became interested in the large number of Proteocephalids which Professor Ward had secured by work in the field and by exchange. The writer had also made some collections. A preliminary study of the available material by the writer was convincing to Professor Ward that a more complete and comparative study of the group was desirable and that the results of such a study would prove of value to helminthologists, not only of America but also in Europe. Such a study seemed more-desirable since but two comparative studies of the group had been made in more than fifteen years, the first by Riggenbach (1896) mostly on the species infesting fish, and the second by Schwarz (1908) wholly on the species infesting snakes and reptiles. The fact that very little had been done on the genus by American investigators furnished an added incentive to undertake the work.
At Professor Ward's suggestion and under his direction the writer undertook an investigation of the genus which would be comprehensive in scope and at the same time comparative. For this purpose Professor Ward augmented the material already at hand by securing the loan of alcoholics and prepared slides from several European and American investigators and from the collections of the Smithsonian Institution and the Bureau of Animal Industry at Washington. Unfortunately, specimens of certain material could not be secured either because it had been lost or because it could not be removed from the collections.
The lack of some of this material has caused the writer to change the plan of the paper somewhat. Instead of making a fresh study of each species it has been necessary in describing certain species to depend on the data secured from the literature. These data have been recombined and quotations have been made, sometimes quite extended, while original drawings which were found useful in presenting the characters and structures of the species have been copied and used in the new account. Possibly it may seem that a consideration of these species might have been omitted without apparently having great effect on the value of the work. The writer found however that serious errors had been made in determination and upon these mistaken determinations identification of other species had been made dependent. The only way of escape from the tangle was to consider every species in the family.
In order that the work might be of more value to many of the American investigators to whom large numbers of the older works of the European writers are unavailable and for the purpose of comparison large extracts from these older writings have been quoted verbatim. For these reasons also the number of drawings copied is larger than at first glimpse seems necessary. The writer has been compelled however to omit because of lack of space many extracts and many drawings which would add to the value of the work. In working over the large literature on the subject an attempt was made to secure every important paper. Some less important papers are known to have been omitted.
Thanks are due to the following investigators who at the request of Professor Ward so kindly sent prepared slides or alcoholics from their valuable collections for study and comparison: Professor Fritz Zschokke, University of Basle, Professor Corrado Parona, University of Genoa, Professor Max Braun, University of Konigsberg, Professor K. M. Levander, Helsingfors, Finland, Professor Anton Collin, University of Berlin, Professor A. E. Shipley, Christ's College, Cambridge, Professor Fr. Sav. Monticelli, University of Naples, Professor 0. Fuhrmann, University of Neuchatel, Dr. C. W. Stiles, Hygienic Laboratory, Washington, D. C., Dr. B. H. Ransom, Bureau of Animal Industry, Washington, D. C., Professor Edwin Linton, Washington and Jefferson College, Professor A. J. Smith, University of Pennsylvania, Professor L. T. Hankinson, Charleston, Ill. Mr. E. G. Davis of Lincoln, Nebraska, and Mr. Herman Douthitt of Sulphur, Oklahoma, have also very kindly furnished material for study. Thanks are due to Mr. S. Fred Prince for re-drawing many of the figures from other works and for making my pencil sketches into the finished drawings.
To the United States Bureau of Fisheries and to its corps of scientific workers I am indebted for encouragement and assistance in many ways, especially in securing valuable material from various sources.
To Professor Henry B. Ward my sincerest thanks are due for the use of his extensive collections, for the use of his library, and also for securing for my use many rare specimens and rare books. His interest and co-operation have given me the inspiration to complete the work.