FAMILY IV. PSEUDOMONADACEAE 193 



Note: Species incertae sedis. At least tons) is listed in the Manual as producing 



twelve additional species that appear to acid and gas from glucose and related 



be identical with or closely related to the sugars. A monographic studj' of these or- 



four species described in full have been ganisms is needed. The descriptions of some 



reported in the literature. These were isola- species that were found before 1900 appear 



ted from water, aquatic animals (midge to be as adequate as are the early descrip- 



larvae, leeches, fishes) or dairy products. tions of Aeromonas liquefaciens. No attempt 



It should also be noted that at least one has been made to determine which specific 



plant pathogen {Xanthomonas proteamacu- epithet or epithets have priority. 



Genus V. Photobacteriuni Beijerinck, 1889, emend. Breed and Lessel, 1954.* 



(Beijerinck, Arch, neerl. d. Sci. exact, et natur., 23, 1889, 401; Photobader Beijerinck, 

 Troc. Sect. Sci., Kon. Akad. v. Wetensch., Amsterdam, 3, 1900, 352; ? Photomonas Orla- 

 Jensen {nomen nudum). Jour. Bact., 6, 1921, 271; Breed and Lessel, Antonie van Leeuwen- 

 hoek, 20, 1954, 60.) 



Pho.to.bac.te'ri.um. Gr. noun phos light; Gr. ueut.dim.n. bacterium a small rod; M.L. 

 neut.n. Photobacterium light (-producing) bacterium. 



Coccobacilli and occasional rods which, in the presence of glucose and asparagine, tend to 

 ramify in a manner analogous to that of bacteroids. Polar flagellate when motile. The type 

 species is normally non-motile but shows motility in young cultures (Kluyver). May or may 

 not liquefy gelatin. Produce acid, or acid and visible gas (H2 and CO2), from glucose and 

 other carbohydrates but not from lactose. Luminescent. Growth and luminescence best, or 

 even exclusively, on salt-water media containing 3 to 5 per cent salt. Found on dead fish 

 and other salt-water animals and in sea water. Reports by various authors indicate that the 

 luminescent^ coccoid and rod-shaped bacteria found living symbiotically in the tissues of 

 the phosphorescent organs of various cephalopods and deep-sea fishes also belong to this 

 genus. Other coccoid and rod-shaped luminescent bacteria found in the blood of Crustacea 

 and caterpillars appear to be parasitic or even pathogenic. 



The type species is Photobacterium phosphoreum (Cohn) Ford. 



Key to the species of genus Photobacterium. t 



I. Coccobacilli which produce acid and gas from glucose. 



A. Saprophytic on dead fish, Crustacea, meat and similar products. 



1. Photobacterium phosphoreum. 



B. Symbiotic, found in the photogenic organ of a cephalopod. 



2. Photobacterium pierantonii . 

 IL Short rods which produce acid but no gas from glucose. 



A. No growth at 37° C. 



3. Photobacterium fischeri. 



B. Grows well at 37° C. 



4. Photobacterium harveyi. 



1. Photobacterium phosphoreum fende het geneeskundig staatstoezicht in 



(Cohn, 1878) Ford, 1927. {Micrococcus Nederland, 1878, 126; Bacterium phos- 



phosphoreus Cohn, see letter addressed to phorescens Fischer, Cent. f. Bakt., 3, 1888, 



J. Penn, Verzameling van stukken betref- 107; Photobacterium phosphorescens Bei- 



* Prepared by Prof. Robert S. Breed and Mr. Erwin F. Lessel, Jr., Cornell University, 

 Geneva, New York, February, 1954. 



t See Speucer (Jour. Gen. Microbiol., 13, 1955, 111) for a recent discussion of the classifica- 

 tion of this group. 



