80 MORPHOLOGY OF THE BACTERIA. 



Ehdbdomonas rosea, Cohn. 



Cells pale pink, isolated, fusiform ; eight times as 

 long as broad, having a length of 20 to 30 //,, and a 

 width of 3.8 to 5 fi; having a slow oscillatory move- 

 ment, the pink substance containing numerous gran- 

 ules of darker color and vacuoles. Hob., stagnant 

 water. 



Ophidomonas sanguined, Ehrb. 



Cells pale pink, spiral, rigid, movement active ; 

 thickness 3 /LI, length of one turn of the spiral, 9 to 

 12 //,. jETa6., brackenish waters of Denmark (Warm- 

 ing)- 



Spiromonas Cohnii, Warming. 



Cells spiral, flattened; 1J turn of spiral, diam. 1.2 

 to 3.5 /x, width 1.2 to 4 /i. Hob., coast of Denmark. 



2. MICROBACTEKIA, Cohn. 



Rod-bacteria, cells cylindrical, short, having spon- 

 taneous movement. 



A single genus, Bacterium. 



g. Bacterium, Duj. emend. 



Cells cylindrical or elliptical, free or united 

 in pairs during their division, rarely in fours, 

 never in chains (leptothrix or torula), sometimes 

 in zooglcea (differing from the Z. of spherical B. 

 by a more abundant and firmer intercellular 

 substance), having spontaneous movements, os- 

 cillatory and very active, especially in media 

 rich in alimentary material and in presence of 

 oxygen. 



