128 



BOTANY. 



224. The Bacteria. — Some of the Fission Algae have be- 

 come much degenerated through being parasitic or sapro- 

 phytic. They are still smaller than those already described, 

 and are colorless. Their miniite cells in some cases measure 

 no more than .0005 mm. (-jTrWir inch) in diameter. They 

 are in som6 species rounded in shape, in others elongated 

 like little rods, or in others more or less /Jurved (Fig. 62). 



Fig. 62.— Forms of Bacteria, a, Micrococcus; 6, Bacterium termo (rest- 

 ing stage) ; c, Bacterium lineola ; d, Bacillus ulna ; 6, Vibrio rugula ; /, 

 Splrocheete plicatile ; g. Spirillum volutans. Magnified 650 times. 



They are frequently proyided with one or two cilia (i.e., 

 whip-like projections of protoplasm), by means of which 

 they move about with great activity. 



225. Bacteria are found in great numbers in the watery 

 parts of decaying organic matter, causing various kinds of 

 fermentation. They reproduce by fission and spores with 

 such astonishing rapidity tha,t in a short time they swarm 



