Jahn, Theodore Louis,  1905- <br/><br/>
How to know the Protozoa :  a pictured-key for identifying the more common fresh water, marine, and parasitic Protozoa, with elementary discussions of the importance of each group and of interesting facts concerning them / 
Theodore Louis Jahn and Francis Floed Jahn. 
 - Dubuque :  W. C. Brown ,  c1949 
 - 234 p. :  illus. ;  22 cm. 
 - Pictured-key nature series .
<br/><br/>Includes index 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Protozoa.
<br/><br/><label>Dewey Class. No.: </label>593  / JHA 1949