SUBGROUPS AND GENERA OF THE BACTERIACEAE 51 



Notwithstanding the force of the above arguments in favor of 

 using the generic name Bacterium for this group, this use will 

 lead to the greatest confusion in the literature. It would seem 

 best to use the name Pseudomonas for this genus, designating 

 Bacterium as a genus conservandum for the colon-typhoid group 

 of bacteria in accordance with the proposal of Orla Jensen (1909a 

 p. 343). This is the recommendation of the Committee on 

 Classification of the Society of American Bacteriologists. 



Genus 2. Serratia Bizio, 1823, emended 



Synonyms : 



Zaogalactina Sette, 1824, p. 51 

 Erythrobacillus. Fortineau, 1905, p. 104 



Cells rod-shaped, without spores. Motile by means of peri- 

 trichous flagella or non-motile. Gram stain variable. Aerobic, 

 producing a red or pink pigment, a lipochrome. Possibly closely 

 related yellow and orange lipochrome-forming bacteria should be 

 included here as well. 



The type species is Serratia marcescens Bizio, the organism 

 usually termed Bacillus prodigiosus. The synonomy of this 

 organism is as follows: 



Serratia marcescens Bizio, 1823 



Zaogalactina imetropha Sette, 1824, p. 51 



Monas prodigiosa Ehrenberg, 1848 



Palmella prodigiosa Montague, p. 727 



Micrococcus prodigiosus Cohn, 1872a, p. 153 



Bacillus prodigiosus Fluegge, 1886, p. '284 



Bacillus imetrophus Trevisan, 1887 



Bacillus marcescens De Toni and Trevisan, 1889, p. 976 



Pfeiffer (1887, p. 46) lists Serratia under Fungi dubiae sedis 

 and ascribes the genus to Bergamaschi. 



Vuillemin (1913, p. 521) concluded that although the char- 

 acters used by Bizio have no generic value, nevertheless the 

 generic name might well be revived to include the rod-shaped 

 bacteria with diffuse flagella. He terms Serratia subtilis {Bacil- 

 lus subtilis) the type o'f his emended genus conservandum. 



