90 



GENERAL BACTERIOLOGY 



2. Cells with polar fla- 



gella-tufts, 11. Spirillum Ehrenb. 



B. Cells flexuous, - 12. Spirochaeta Ehrenb. 



(3) Cells inclosed in a sheath. Chlamydobacteeiaceae 



MiGULA. 



A. Cell contents without gran- 

 ules of sulphur. 



a. Cell threads unbranched. 

 1). Cell division always 



only in one plane, 13. Streptothrix Cohn. 



2 ) . Cell division in three 

 planes previous to 

 the formation of co- 

 nidia. 



i). Cells surrounded 

 by very delicate, 



scarcely visible 

 sheath (marine). 



ii). 



Sheath clearly 

 visible ( fresh wa- 

 ter), 



b. Cell threads branched, 



b. Cell contents containing sul- 

 phur granules. 



(4) Cells destitute of a sheath, 

 united into threads mo- 

 tile by means of an un- 

 dulating membrane. 



Only one genus, 



14. Phragmidiothrix Eng- 



LER. 



15. Crenothrix Cohn. 



16. Cladothrix Cohn. 



17. Thiothrix Winograd- 



SKY. 



Beggiatoaceab Trevisan. 

 18. Beggiatoa Trevisan. 



