PREFACE 



STUDY of Protozoa was formerly considered as belonging ex- 

 clusively to the domain of graduate students in zoology, but 

 as a result of the tremendous advance in our knowledge of 

 protozoan parasites of man and domestic animals in the last 

 fifteen years, a number of universities and colleges have begun 

 to offer courses dealing with both free-living and parasitic 

 Protozoa to advanced students. For some years the author has 

 taught such a course at the University of Illinois. The classes 

 are composed chiefly of advanced students who have had at 

 least one year of zoology and are majoring in zoology, botany, 

 bacteriology, entomology or premedical curriculum. Although 

 some admirable works on {^rotozoology have appeared in recent 

 years, no one of them would afford adequate guidance through- 

 out a course of this kind. Most modern publications on the 

 subject emphasize the parasitic forms and do not give much space 

 to the taxonomy, biology, and orientation of the free-living 

 forms from which the parasitic group undoubtedly evolved. 



The aim of the present work is, therefore, to provide a 

 handbook of introductory information on the common and 

 representative genera of all the groups of both free-living and 

 parasitic Protozoa. The author claims little originality in the 

 material employed, for it is mainly compiled from data already 

 known. 



The text is divided into two parts: The first part consists 

 of three chapters giving a general account of the morphology, 

 physiology and reproduction of Protozoa. The treatment here 

 is brief, since there are several excellent treatises on this part 

 of protozoology, such as Calkins' The Biology of the Protozoa. 

 Furthermore, the student has neither time nor need for ex- 

 tended discussion at the beginning of the course. The second 

 part, which is composed of thirty chapters, is concerned with 

 the taxonomy, biology and development of common Protozoa. 

 Differentiation of classes, orders and families is carried on by 

 keys. In some genera which are of common occurrence, such 

 as Amoeba, Entamoeba, Arcella, Euglena, Paramecium, Chilo- 

 don, Vorticella, etc., several species are mentioned. 



