viii PR?:FACK 



tions were taken. In order to increase the reference value, all 

 figures are accompanied by scales of magnification which are uni- 

 formly somewhat greater than those of Handbook of Protozool- 

 ogy, since the microscope now used in the class-room has been 

 improved upon in recent years. 



The list of references appended to the end of each chapter has 

 been enlarged and is meant to aid those who wish to obtain fuller 

 information than that w^hich is given in this volume. Since com- 

 prehensive monographs on various groups of Protozoa are widely 

 scattered and ordinarily not easily accessible, the author has en- 

 deavored to provide for each group as complete an information as 

 possible for general reference purpose within the limited space, 

 and hopes that the present work has reference value for teachers 

 of biology, field workers in pure and applied biological sciences, 

 veterinarians, physicians, public health workers, laboratory tech- 

 nicians, and others. 



The author is under obligation to numerous writers for their 

 valuable contributions which have been incorporated in the text. 

 Special thanks are due Professor L. R. Cleveland, Harvard Uni- 

 versity; Professor R. P. Hall, New York University; Professor 

 H. Kirby, Jr., University of California; Professor L. E. Noland, 

 University of Wisconsin; Professor H. J. Van Cleave, University 

 of Illinois; Professor D. H. Wenrich, University of Pennsylvania; 

 and Professor L. L. Woodruff, Yale University, for their valued 

 criticisms and suggestions. The author further wishes to express 

 his appreciation to Mr. Charles C Thomas, for his patient and kind 

 cooperation which has aided greatly in the completion and ap- 

 pearance of the present work. 



R.R.K. 

 Urbana, Illinois, U.S.A. 

 July, 1939 



