CHAPTER II 



INTESTINAL AMCEB^ 



I. Generic Characteristics 



Practically all protozoologists agree that there are at 

 least six "good" species of amoebae that are natural para- 

 sites of man. Besides these there are a number of doubt- 

 ful species that have been described from man but about 

 which there is as yet no general agreement. The six good 

 species are illustrated in Figs. i-6. They have been placed 

 in four genera although there is still some doubt about 

 the validity of several of these genera. Any one v^ho 

 v^^ishes to become informed regarding the classification 

 of the parasitic amoebae should consult the following 

 books: Dobell (1919a), Hegner and Taliaferro (1924), 

 and Wenyon (1926). Detailed accounts of the morphol- 

 ogy and life histories of these amoebae are also to be 

 found in these books, hence only a brief statement of 

 their distinguishing characteristics will be included here. 

 The structure of the nucleus is the most important cri- 

 terion used in distinguishing the different genera. 



I. endamcEba 



This genus possesses a spherical nucleus with a small 

 karyosome of chromatin and a superficial layer of chro- 

 matin granules lying on the inside of the nuclear mem- 

 brane. In fixed material a clear area is present around 



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