138 



SULPHUR BACTERIA 



feature selected as a basis for division. At first three species 

 were distinguished and named as follows : — 



Monas Okenii, 7-5 — 15/x X 5/x. 



Monas vinosa, 2'^ijl long. 



Monas Warniingii, somewhat longer than the first. 



The genus was removed from the Flagellates, renamed 

 Chromalutm by Perty, and placed among the Bacteria. Perty 



Fig. 25.^ — Lankesteron sulfuratum (Warming), Ellis. 

 Syn. Bacterlxtm sulfuratum (Warming). 



Some of the hundreds of the different forms figured by Warming as 

 pleomorphic forms of this organism. The figure marked a is the 

 Rhahdomonas of later writers. 



added to the genus two other species, which he named 

 Chromatium Weissii and Chroinathini violascens. Later the 

 number was added to by Winogradsky, who named Chro- 

 matium minus and Cliromaiium minutissimum ; and within 

 recent years Chr. Linsbaueri was added by Gicklhorn, Chr. 

 gracile by Strzeszewski, and Chr. Gobie by Issatchenko. 



Description. — Coloured, free, motile cells, normally of ellip- 

 soidal-cylindrical form, but subject to considerable variations 



