THE CLASSIFICATION OF BACTERIA 379 



2. Thiothrix nivea (Rabenhorst) Winogradsky 



Beggiatoa nivea Rabenhorst : Kryptogamen flora, I. 

 Thiotrix nivea Winogradsky : I.e. 



laments with a thin sheath, 2-2.5 M broad at the base, and 1.4-1.5 \l broad 

 at the apex; often 100 /t long, segmented at the apex, producing motile 

 gonidia 8-9 [i. long. 



abitai^ Found in sulphur and stagnant water. 



3. Thiothrix tenuis Winogradsky 



[laments very long, and about i .0 in diameter. 

 'abitat. Found in sulphur water. 



BEGGIATOACE^E Migula 



ilamentous bacteria. Filaments without sheaths, but with motility like Os- 

 cillaioria by means of an undulating membrane. The cell contents show 

 the presence of sulphur granules. The formation of gonidia not known. 



BEGGIATOA Trevisan 



Prospetto della Flora Euganea, 1842, 76. 



[laments apparently not segmented except when stained with iodine. Color- 

 less, or faintly rose-colored. 

 . Filaments colorless. 



A. Filaments 3-4 microns thick. 



1. Beggiatoa alba (Vaucher) Trevisan. 



B. Filaments 7 microns thick. 



2. Beggiatoa arachnoidea (Agardh) Regensburger. 

 C Filaments 16 microns thick. 



3. Beggiatoa mirabilis Cohn. 

 . Filaments colored reddish-violet. 



4. Beggiatoa roseopersicina Cohn. 



I. Beggiatoa alba (Vaucher) Trevisan 



Flora Euganea, 1842. 

 ilaments long, 3-4 [x. thick, containing numerous strongly refracting granules 

 of sulphur. Filaments break up into short segments, which then grow 

 out into longer threads. Sulphates reduced to H2S and to free sulphur. 



