295] PSEUDOPHYLLIDEA FROM FISHES— COOPER 



INTRODUCTION 



Soon after commencing the study of Haplobothrium globulijorme Cooper the 

 writer (1914, 1914a) saw that, apart from the early and somewhat brief 

 reports and descriptions by Leidy and the later, but yet pioneer work of Linton 

 on both marine and fresh-water species, very Httle had been done on the mem- 

 bers of the order in America. Consequently the desire for an opportunity 

 to work up other species which had in the meantime been collected at the 

 Canadian Lake Biological Station on Georgian Bay, located at Go-Home Bay, 

 Muskoka District, Ontario, and at the Marine Biological Station at St. And- 

 rews, New Brunswick, grew with the feeling that something of a comprehensive 

 nature ought to be undertaken in order not only to ascertain to what extent 

 European species are to be found in this contment, but also to locate properly 

 in the classification at least some of the new forms formerly described, especially 

 by Linton. Altho the material then at hand was investigated to a certain 

 extent at the University of Toronto, it was not until the writer came 

 to the University of Illinois that it was studied at all thoroly with the aid of 

 other material for comparison from the collection of the University of Illinois, 

 under the care of Professor Henry B. Ward. 



Supplementary material, which in many cases was all that was available, 

 was obtained by Professor Ward from the United States National Museum 

 and the Bureau of Animal Industry, but apart from a few vials no European 

 specimens could be procured, ovnng to the present international conflict. On 

 account of the lack of the latter most of the determinations have been made 

 with the aid of the literature only, a fact which the writer feels may necessitate 

 future changes in connection with a few species which have been more or less 

 tentatively regarded to be the same as those in Europe. In all cases, however, 

 the specific details of the American forms have been emphasized, so that if 

 changes have to be made later, the basis for such will be at hand. The writer 

 would like to point out in this connection the comparative lack from a systema- 

 tic standpoint of adequate descriptions of many of the European species which 

 have been known for many years. It was this fact which in the absence of 

 the original material for comparison made the present work one attended with 

 not a little difficulty. 



In the main the classification of the order adopted by the writer is that 

 proposed by Liihe (1902) and later (1910) retamed with only a few modifica- 

 tions. The family of the Caryophyllaeidae is, however, not included, so that 

 the order is considered to be rather that of Carus (1863), with Luhe's later 

 conceptions of the other families. One of the latter must now again be modified 

 considerably owing to the present study of two quite aberrant species, namely, 

 Haplobothrium globuliforme Cooper and Marsipometra hastata (Linton) which 

 have been found by the writer to be very disturbing to the classification. 



The writer wishes here to tender his thanks in the first place to the Biological 

 Board of Canada for placing means and faciUties at his disposal in connection 



