124 TAXONOMY 



biologists class them as animals. Structures called sporangia, 

 containing minute microscopic spores which are provided 

 with a cell wall, a nucleus, protoplasm, and capable of generat- 

 ing a new body, are present. These bodies are only slightly 

 resistant and are specific reproductive cells. They do not 

 serve to carry the organism over unfavorable periods as the 

 endospores of bacteria do. Reproduction among the bac- 

 teria is a much simpler process than it is in the slime molds. 

 The Myxomycetes do not resemble the bacteria closely. 



Relationship to Myxobacteriaceae. - - The myxobacteria 

 are rodlike organisms which are motile and multiply by fis- 

 sion. They secrete a firm gelatinous base and often form 

 aggregates of several cells. The formation of these aggrega- 

 tions of cells usually precedes a stage in which the rods be- 

 come encysted and go into the resting stage or become en- 

 cysted and form spores. The. cells undergo elongation and 

 constriction in the center before division and never remain 

 attached together in chains. The organism moves in a glid- 

 ing fashion not unlike Beggiatoa. Locomotor organs are 

 unknown. The masses of the cells are reddish in appear- 

 ance. Myxobacteria are common in moist places, as on 

 decaying wood or on fungi. Their optimum temperature is 

 about 30 C. This group of microorganisms connects the 

 higher or Thiobacteria and the Cyanophyceae or blue-green 

 algae and the Myxomycetes or slime molds. This group 

 (Myxobacteria) is sometimes made to constitute a third order 

 under the bacteria. 



