PROCEEDINGS OE THE DAVENPORT ACADEMY OF SCIENCES 



Davenport. louAa, September. 1906 Vol. XI. Pages i-124 



THE PROTOZOA OF IOWA. 



A STUDY OF SPECIES KNOWN TO OCCUR IN THE WATERS 

 OF THIS STATE 



Bv CHARLES HOWARD EDMONDSON. 



A THESIS 



Submitted to the I'aculty of the Graduate College of the State University 

 of Iowa for the Degree of Doctor of Philosophy. 



INTRODUCTION. 



To the zoologist the Protozoa which swarm the seas and are 

 found abundantly in inland rivers, lakes, ponds and pools, adapt- 

 ing themselves to nearly every condition of moisture, offer an 

 interesting and fruitful field for investigation. 



The one-celled animals concern the student of Nature not only 

 because of their position in the scale of animal life ; not only by 

 reason of their economic value both positive and negative, but 

 also because many of the phenomena exhibited by highly spe- 

 cialized life can be explained only by a knowledge of the charac- 

 teristics and behavior of these lowly organisms. 



Although discovered in 1675 by Leeuwenhoek, the unicellular 

 nature of the Protozoa was not declared with assurance until 

 1848, but within recent years these one-celled animals have not 

 been unitnportant factors in solving puzzling biological problems 

 when subjected to skilful and patient experimental work. Espec- 

 ially have the Protozoa been a means of advancing the knowl- 

 edge concerning the animal cell by the careful labor of many 

 devoted students of science, and as a result of the concentration 

 of attention upon the simplest of microscopic animals problems of 

 a diverse and complex character have arisen. There is .some 



[Proc. D. A. S., Vol. XI.J i [April i8, 1906.] 



