Taxonomy 



All strains of light producing bacteria appear to be carbohy- 

 drate fermenters and polar flagellated. They could thus be classi- 

 fied either in the genus Vibrio or Aeromonas. On the bases of 

 somatic morphology and sensitivity to a vibrio static substance 

 (2,4-diamino-6,7-diisopropylpteridine), Spencer would classify P. 

 sepioe and P. horveyi in the Aeromonas genus and the others in 

 the Vibrio genus. As recorded in Table XII the flagellar wave- 

 lengths of P. horveyi and P. sepiue are much alike and distinctly 

 different from the others, which lends support to the Spencer 

 classification. The flagellation of P. fischeri, however, is different 

 from any typical Vibrio species and more like spirilla. 



Flagellar Characteristics 



P. fischeri showed polar multitrichous flagellation. The flagella 

 were short, with few curves, usually less than one complete wave, 

 and of very long wavelength. Some individuals were short spiral 

 forms, others practically spherical. The somatic morphology and 

 flagellation resemble the marine spirilla in which the spherical 

 form, or microcyst, is quite usual. P. phosphoreum, both the 

 Spencer strain and the two Kluyver strains, showed a spherical 

 soma and a single flagellum of somewhat longer than the average 

 wavelength of most polar monotrichous bacteria. By observing 

 the location of the flagellum in dividing forms it was evident that 

 the flagellum had a polar location. P. albensis showed a variety 

 of somatic types — small straight rods, small curved rods, and long 

 spiral filaments. On the small forms the flagellation was polar 

 monotrichous with about SO^o of the organisms being amphi- 

 trichous. The long spiral forms frequently showed tufts of flagella 

 characteristic of spirilla. P. harveyi was a large straight rod with 

 polar monotrichous flagella. The size of the soma and the curva- 

 ture of the flagella showed great variation. P. sepiae showed only 

 straight rods with polar monotrichous flagella. The flagellar wave- 

 length was rather variable and may be of two types. P. splendi- 

 diim showed a very pleomorphic soma with spherical forms, 

 straight and slightly curved rods, and definitely spiral forms. 

 The flagellation was polar monotrichous without the flagellar tufts 

 seen in P. albensis. None of the cultures examined showed any 

 very definite flagellar variants. 



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