NON-FILAMENTOUS SULPHUR BACTERIA. 367 



201. Morphology of the Non-Filamentous Sulphur 

 Bacteria. 



Several red species of these organisms are already known to us 

 (91), viz., Chromatium (Monas) Ohenii, Monas Warmingii, Spiril- 

 lum rubrum, Sp. volutans, Ophidomonas sanguined, Rhabdomonas 

 These are again shown in Figs. 74 to 78. It was remarked 



rosea. 



in 68 that Ray Lankester had assumed all these organisms to be 

 merely special forms of one species for which he proposed the name 



no. 74. 



Chromatium Okenii. 

 Magn. 600. (AfterF. Cohn.) 



U 



FIG. 75. 



Rhabdomonas rosea. 

 Magn. 600. (AfterF. Cohn.) 



FIG. 7 6. 



Monas Warmingii. 

 Magn. 600. (AfterF. Cohn.) 



FIG. 77. Spirillum volutans. 

 Magn. 600. (After F. Cohn.) 



i FIG. 78. Ophidomonas sanguinea. 

 Magn. 600. (After F. Cohn.) 



Bacterium rubescens. The basis for this assumption was, however, 

 a very insufficient one, since it rested principally on the identity 

 (which, moreover, was not satisfactorily demonstrated) of the red 

 colouring matter, peculiar to these organisms, and which received 

 from Lankester the name bacterio-purpurin. This investigator 

 was supported in his views by Warming (in 1875), who on his 

 part classified a large number of the red sulphur bacteria examined 

 by him into a single species, viz., Bacterium sulfuratum. Zopf 

 (in 1882) went still farther than either by defining all these 

 organisms as special forms of growth of a single species of thread 

 bacterium, viz., Beggiatoa roseo-persicina, which, under certain cir- 

 cumstances, was said to appear as long threads (Leptothrix), and 



