The citation of numbers for measurements and numbered structures 

 are generally given in the translation as they were in Professor Bychowsky's book. 

 This should further facilitate checking with the Russian. 



Aside from the fact that the text is occasionally interlarded with 

 references to dialectical materialism which seems to have little place in this or any 

 other scientific paper. Dr. Bychowsky has produced the best, most comprehensive 

 treatise on monogenetlc trematodes ever offered to science. Besides being an 

 excellent account of the biology and systematlcs of these interesting parasites, 

 the sections on host-parasite relationships and the historical aspects of the general 

 phenomenon of parasitology are noteworthy. Bychowsky's determinations of the 

 phylogenetlc relationships among and between the parasitic groups of the Phylum 

 Platyhelmlnthes and the free -living turbellarians are extremely Interesting. Thus, 

 though the book is devoted chiefly to the Class Monogenoidea (Beneden) Bychowsky, 

 1937, It is a significant contribution to all parasitology. 



Thanks are due to Miss Patricia R. Conner of the Virginia Institute 

 of Marine Science who transcribed, typed, and assembled the manuscript, and to 

 Mrs. Ellen Oustinoff, who assisted with final editing. 



William J. Hargls, Jr. 

 Laboratory Director and Dean 

 School of Marine Science of the College 

 of William and Mary in Virginia 



VII 



