60 CLASSIFICATION 



3. Family: SpiEiLLACEyE Migula, all spirilla. 



Genus 1. Spirospma Migula: non-flagellated; non-motile. 

 " 2. Microspira (Schroter) Migula: flagella one to 

 Cells stiff ] three at the end (Fig, 53). ' 



" 3. iSpiritom (Ehrenberg) Migula: flagella more than 

 three at the end (Fig. 54) . 

 C II flp ihl / " ^' ^virochmla Ehrenberg: motile; no flagella (Fig. 



55). 

 4. Family: Chlamtdobactekiace.s!. 



Cells cylindrical in long threads, and surrounded by a 

 sheath. Reproduction also by gonidia formed from an 

 entire cell. '' 



Genus 1. Chtamydothrix Migula (Fig. 56). 



" 2. Crenothrix Colin (Fig. 57) . 



" 3. Pragmidiothrix Engler. 



" 4. SpheroHlus (including Cladothrix). 



ORDER II. TfflOBACTERIA: SULPHUR BACTERIA. 



Cells without a nucleus, but containing sulphur granules, 

 may be colorless or contain bacteriopurpurin and be colored 

 reddish or violet. 



1. Family Bbgqiatoace.b. 



Genus 1. Thiothrix Winogradsky. 



" 2. Beggiatoa Trevisan. Of interest since it is with- 

 out a sheath, is motile, but without flagella 

 (Fig. 58). 



2. Family RHODOBACTERiACE.ffii. 



This has five subfamilies and twelve genera, most of which 

 are due to the Russian bacteriologist Winogradsky who did 

 more work than anyone else with the sulphur bacteria. 



