CLASSIFICATION OF MICROORGANISMS 



79 



bearing bacillus. Sometimes a non-motile organism is found to 

 be physiologically, culturally, and morphologically closely related 

 to some motile form, and it seems to be undesirable to separate 

 these into different genera. The differentiation on the basis of 

 spore formation has not been generally accepted by bacteriologists. 

 The term Pseudomonas is sometimes used to indicate a motile 



0. 



Fig. 43. Types of bacilli: a, 6, Non-motile bacilli (Bacterium); c, mono- 

 trichous bacillus (Pseudomonas); d, lophotrichous bacillus (Pseudomonas); 

 e, f, peritrichous Bacillus. 



bacillus having polar flagella, while the term Bacillus is limited 

 to organisms having flagella over the entire surface of the body 

 (peritrichous). The term Bacillus is here used to include both 

 Bacterium and Pseudomonas. 



Spirillum. The family Spirillaceae is divided by Migula into 

 four genera: Spirosoma is non-motile. Microspira is a rigid, 



Fig. 44. Types of spirilla: a, Non-motile spirillum (Spirosoma); 6, mono- 

 trichous spirillum (Microspira, Vibrio) ; c, lophotrichous spirillum with 2 or 3 

 flagella (Microspira, Vibrio); d, lophotrichous spirillum (Spirillum). 



short, comma-shaped organism with one, two, or three flagella. 

 Vibrio is sometimes used as a synonym of microspira. Spirillum 

 is used to indicate a long, rigid, spiral bacterium with a tuft of 

 flagella at one or both ends. As used in this text, the term Spir- 

 illum will include Spirosoma, Microspira, Vibrio, and Spirillum. 



