76 GENERAL SYSTEMATIC BACTERIOLOGY 



A. Family, Beggiatoaceae: Motile by an undulating membrane, filamen- 



tous colonies of colorless, sheathless cells, with sulfur granules. 

 Genera: Beggialoa, Thiothrix. 



B. Family Rhodobacteriaceae: Cell content rose, red, or violet with sulfur 



granules. 



Genera; Lamprocystis, Thiosarcina, Rhodohacillus, Thiospirillum, 



Chromatium. 



Meyer (1912, p. 2) recognized as an order the Euhacteria the genera 

 and generic sections of which may be separated by the following key: 



Key to the genera and sections of the Euhacteria according to Meyer (1912) 



a. Cells straight rods. 



b. Not with polar flagella. Flagella when present-peritrichous. 



Genus Bacillus 

 c. Cells containing bacteriopurpurin. 



Section Rhodohacillus 

 2c. Cells not containing bacteriopurpurin. 

 d. Flagella unknown. 



Section Bacterium 

 2d. All other species. 



Section Eubacillus 



2b. With polar flagella Genus Pseudomonas 



2a. Cells not straight rods, 

 b. Cells curved rods. 



c. Peritrichous flagella, with spores. 



Genus Spirobazillus 

 2c. Polar flagella, spores unknown, 

 d. With 5-20 polar flagella. 



Genus Spirillum 

 e. Without bacteriopurpurin. 

 f. Flagella unknown. 



Section Spirosoma 

 2f. Flagella known. 



Section Euspirillum 

 2e. With bacteriopurpurin. 



Section Rhodospirillum 

 f. Sulphur free. 



Subsection a 

 2f . With sulphur. 



Subsection j8 

 2d. With 1 rarely 2-3 polar flagella. 



Genus Microspira 

 e. With bacteriopurpurin. 



Section Rhodospira 

 2e. Without bacteriopurpurin. 



Section Eumicrospira 



