BACTEKIA III 



Genus: Bacillus Cohn. 



The cells are cylindrical, of longer or shorter length. The rods are sometimes 

 oval in shape. Cells are motile and possess flagella which are distributed over the 

 entire surface. Endospore formation occurs with marked regularity. The bacteria 

 in this genus are motile only during certain periods of their life. This period varies 

 greatly in length and occurs only in the vegetative stage. 



Genus : Fseudomonas Migula. 



The cells are cylindrical, of longer or shorter length. The cells are motile and 

 possess polar flagella. These flagella may vary from one to twelve in number. The 

 formation of endospores in this species is claimed by some. If they occur, it is ex- 

 tremely rare. Occasionally certain species in this genus form themselves into threads 

 or chains. 



III. Family : Spirillacese 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 fuU 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 nde 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 Sckbotee. 



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 

 flagellum and rarely two or three flageUa. These flagella are about the same length 

 as the cell. No endospores are formed. Some writers make no distinction between 

 Microspira and Spirillum. The name Vibrio has also been applied by some writers 

 to this genus. 



Genus : Spirillum Ehrenbero. 



The cells are rigid, usually long and forming long, screw-like threads, or, in some 

 cases, only portions of a spiral turn. Cells are motile and possess a tuft of flagella 

 at the pole. The flagella may occur at both ends of the spiral, and they vary greatly 

 in number. Endospore formation has been observed in some species. 



Genus : Spirochaeta Ekrenbeeg. 



The cells are flexible spirals, very thin and long. No flagella are present. These 

 bacteria move by rotation similar to a screw, and also by lateral motion similar to 

 a snake. The locomotive organs, if present, are not known. No endospores are 

 produced. 



II. Suborder: Trichobacterinae (higher bacteria). 



Family: Chlamydobacteriaceae Migula. 



The cells are cylindrical, are united in threads, and surrounded by a sheath. 

 Reproduction takes place by means of motile and non-motile gonidia. , These gonidia 

 arise directly from the vegetative cells and, without any resting stage, produce new 

 threads of cells. 



