34 ORDER I. PSEUDOMONADALES 



2. Cells in trichomes. 



Order VI. Caryophanales, p. 830. 

 B. Not as above. 



1. Cells rigid and maj- grow out into a branching mycelium-like .structure which 

 may even develop chains of aerial conidia giving colonies a superficial resem- 

 blance to mold colonies. In two genera spores develop within sporangia (sporan- 

 giospores), and in one of these genera the spores are motile. Where cells occur 

 singly or in simple branched forms, they are frequently acid-fast. 



Order V. Actinomycetales, p. 694. 



2. Not as above. 



a. Cells rigid, usually large and may occur as coccoid cells or trichomes. Sulfur 

 granules may occur on the surface or within the cells. Move by a gliding, oscil- 

 lating or rolling, jerky motion like that of some blue-green algae. No flagella 

 present. 



Order VII. Bcggiatoales, p. 837. 

 aa. Not as above. 



b. Longer or shorter flexuous cells. 



c. Cells flexuous, creeping on a substrate. Frequentlj^ pointed at both 

 ends. Fruiting bodies are usually developed from a thin spreading 

 colony (pseudoplasmodium). Slime bacteria. 



Order VIII. Myxobacterales, p. 854. 

 cc. Cells in the form of longer or shorter spirals. Swim freely by flexion of 

 cells. 



Order IX. Spirochaetales, p. 892. 

 bb. Non-motile, highly pleomorphic organisms of a very delicate character. 

 Possess filterable stages. 



Order X. Mycoplasmatales, p. 914. 



