108 TAXONOMY 



may vary from one to twelve in number. The formation of 

 endospores in this species is claimed by some. If it occurs it 

 is extremely rare. Occasionally certain species in this genus 

 form themselves into threads or chains. 



III. Family: Spirillaceae Migula. 



The cells are wound in the form of a spiral or representing 

 the portion of a turn of a spiral. In the latter case, if the cells 

 remain attached together in the form of a thread, a full spiral 

 of several turns is produced. Cell division takes place in only 

 one direction of space, and this is transverse to the long axis 

 of the cell. 



Genus: Spirosoma Migula. 



The cells are rigid and bent in the form of spirals. The 

 members of this genus are as a general rule quite large. The 

 cells may be free or united together into small gelatinous 

 masses. Some of the cells individually are surrounded by 

 a gelatinous envelope while others are free. 



Genus : Microspira Schroter. 



The cells are rigid, short, and bent similar to a comma. 

 When the cells are united together, S-shaped threads are 

 formed. The cells are motile, possessing usually one flagel- 

 lum and rarely two or three flagella. These flagella are about 

 the same length as the cell. No endospores are formed. 

 Some writers make no distinction between Microspira and 



