22 



POSITION— RELATIONSHIPS 



called a cyst, it is enabled to withstand much greater environ- 

 mental changes than the active organism can, especially 

 drying. The bacterial spore resembles these protozoal cysts 

 very closely. 



Fig. 15. — Penicillium type of mold. X 100. a, branched conidiophore. 



Fig. 16. — Same as Fig. 15. 

 b, conidia. 



Fig. 17. — Higher bacteria. 

 X 1000. The fine branching 

 X 1000. threads are characteristic, a, 

 conidium. 



Some bacteria have the power of independent motion from 

 place to place in a liquid, they can swim, as many protozoa 

 can. Other low plant forms, as some diatoms and desmids 

 and certain green algse, also have motility so that this 

 characteristic is not sufficient to place the bacteria with the 

 protozoa, though the motility of bacteria is more like that of 

 the protozoa than that of the protophyta. 



