28 THE FLORA OF NEBRASKA. 



Bacillus tremulus Koch in Cohn Beitr. II., 3, 417. 1877. 

 Cor nil in tremula Trey. Gen. 22. 



Cells short-cylindrical, or oblong, very small, 2-3x.5.6 ft, characterized by a 



peculiar rotary motion; spores intercalated, terminal. 

 In decomposing solutions. 

 Bacillus snbtilis (Ehrenb.) Cohn Beitr. I, 2, 175 t. 3 f. 14. 1872. 

 Vibrio subtilis Ehrenb., Abhaudl. Akad. Berl. 1831. 



Cells long-cylindrical, .8-1x6 10 //, motile, single or concatenate, often grow- 

 ing out into long filaments (20-40 n), which form an ovoid spore (1.5x2.5 //) 

 at one end, and then break up into minute rods 3-4 /i long. 

 In old yeast cultures. 



6. SPIRIL.L.UJI Ehrenb. Abh. Akad. Berl. 1830, p. 38. 



Cells elongate, cylindrical, more or less strongly spirally coiled, moving very 



rapidly by means of a twisting motion; spores endogenous. 

 Etymology: Latin, diminutive of spira, coil. 



Spirillum rngula (O. F. Muell.) Ehrenb. 1. c. 

 Vibrio rugula O. F. Muell. Verm. Hist. 43. 



Cells cylindrical, very strongly arcuate, or once spirally coiled, 8-13x1.5-2 fi, 



free, actively motile. 

 In stagnant creek water. 



Spirillum nmlnla (O. F. Muell.) Ehrenb. 1. c. 



Cells 8-16 fi long, 1-1.5 n thick, with 1)^-4, or even 6 spiral coils; free, each 



coil 4-5 fi high. 

 In stagnant creek water. 



7. RASMITSSEXIA Trevisan in Sacc. Syl. Fung. VIII., 930. 1889. 



Cells elongate-cylindrical, flexuose, simple, with a thin, gelatinous sheath, of- 

 ten separating into bacilli or cocci, from which the arthrospores arise. 

 Etymology: dedicated to Rasmussen, a Danish bacteriologist. 



Rasimisscnia buccalis (Rob. & Leb.) Trev. 1. c. 



Leptothrix bueeulis Rob. & Leb. in Robin. Hist. Veg. Paras., 315 t. I., f. 1-2. 1847. 

 Cells filamentous, 1-2 /i diam., with a slow, oscillating movement, often im- 

 mobile, forming a dense zoogloea. 

 In decaying teeth. 



