1 14 TAXONOMY 



Genus : Amcebacter Winogradsky. 



The cells are united into colonies, and after division in one 

 direction of space remain attached together by threads of 

 protoplasm. The colonies possess amoeboid motility. The 

 cells change form by contraction and the spreading out of 

 the protoplasm. 



Genus : Thiothece Winogradsky. 



The colonies are inclosed by a thick, gelatinous cyst. The 

 cells are capable of moving and are very loosely surrounded 

 by a common gelatin. 



Genus : Thiodictyon Winogradsky. 



The colonies are solid, nonmotile, and consist of small cells 

 which are pressed together. 



V Subfamily Chromotiaceae. 



The cells are free and capable at all times of motility. 



Genus : Chromatium Perty. 



The cells are moderately thick, elliptical, or cylindric-ellip- 

 tical in shape. 



Genus : Rhabdochromatium Winogradsky. 



The cells are free, rod-shaped, or spindle form. They 

 possess flagella on the poles and are motile at all times. 



Genus: Thiospirillum. 

 The cells are free, continually motile, and spirally twisted. 



