2. Cells with polar flagella 



B. Cells flexuo 



(4) Chlaraydobac 



A. Cell conten 



1. Cells surrounded by a 



very delicate, scarcely 



visible sheath (marine) 2. Phragmidiothrix. 



2. Sheath clearly visible 



(in fresh water) 3. Crenothrix. 



b. Cell threads branched 4. Cladothrix. 



B. Cell contents containing sulfur gran- 

 ules 5. Thiothrix. 

 (5) Beggiatoacese 



Only one genus known (Beggiatoa Trev.) which is scarcely separa- 

 ble from Oscillaria. Character as given under the family. 



This scheme is simple in comparison with that of Fischer, but to fully 

 appreciate it one should compare it with that of de Toni and Trevisan 

 in Saccardo's Sylloge Fungorum, where cumbrousness and triviality 

 reach a climax, these authors breaking up the group into no less than 



From among the various general statements we cull the following : 

 For the most part the wall of the cell is formed not out of cellulose or 

 any similar carbohydrate, but out of albuminoids. The wall may, 

 however, contain embedded in its substance variable quantities of a 

 carbohydrate coloring blue with iodine. There is no " centralkorper " 

 in the true bacteria, but vacuoles have frequently been mistaken for 

 such bodies. Most bacterial pigments are non-nitrogenous bodies 

 related to the analin colors; others are nitrogeneous substances related 

 to the albuminoids, such apparently are the fluorescent pigments. The 

 manner of cell division is a fundamental distinction between Bacteria- 

 cese and Coccacese. Cell division always takes place at right angles to 

 the longitudinal axis when any such is clearly visible. With few 

 exceptions motility is accomplished by means of flagella. These are 



