290 GENERAL SYSTEMATIC BACTERIOLOGY 



to Pasteurella Trevisan (q.v.). One species only is given: Dicoccia 

 glossophila Trevisan. This is the "Bakterien menschlichei- Mundsecrete, 

 zweite Art" of Fliigge (1886, p. 258). It is probable that this organ- 

 ism should be included with the hemorrhagic septicemia forms although 

 the specific determination is not practicable from Fliigge's description. 

 This would make Dicoccia a synonym of Pasteurella. The genus is 

 rejected by Erwin F. Smith (1905, p. 174). 



Didymohelix. A generic name proposed by Griffith (1853, p. 438) 

 for the organism termed Gallionella ferruginea by Ehrenberg, Gloeotila 

 by Kiitzing and Meloseira ochracea by Ralfs. He points out that each 

 of these authors included this species with others of the genus among the 

 diatoms. This organism, as it is not a diatom, cannot be included 

 either in Gallionella or Gloeotila. He notes that the organism usually 

 has the appearance of two intertwined filaments, and proposes the name 

 Didymohelix. For discussion of the synonymy, see Gallionella. 



Buchanan (1918, p. 304) recognized this as the second genus of the 

 family Chlamydobacteriaceae with the following diagnosis. 



Filament twisted, simple, or two filaments, twisted together. Young cell 

 colorless, later yellow brown to rust red through deposition of iron. Simple fila- 

 ments show no division into cells, even when iron is removed with acid and stain 

 applied. Sheath not demonstrable. 



The type species is Didymohelix ferruginea (Ehr.) Griffith. 



DifEusionsbacillus. A casual name used by Beijerinck (1893, p. 

 830) Enlows states: "A species closely related to B. verlihratus. Prob- 

 ably did not intend to use it as a generic name." 



Diplectridium. A genus of bacteria created by Fischer (1895, p. 

 2) to include those rod-shaped organisms having diffuse flagella which 

 become clavate when spores are produced, one spore being formed in 

 each end of the ceU. No species apparently have been described within 

 this genus and the name itself has been abandoned by Fischer in 

 later publications (1903). This generic name is to be regarded as a 

 nomen nudum and invahd. It is rejected by Erwin F. Smith (1905, 

 p. 174). 



Enlows (1920, p. 147) states the type to be "B. solmsii Klein." 



Diplobacillus. Maggi (1886, p. 174) used this term in designating 

 a growth form of a Bacillus. Apparently it was first used as a generic 

 name by Weichselbaum (1887, p. 212) in the combination Diplobacillus 

 brevis endpcarditidis to designate a short rod which occurred in pairs 

 and was apparently associated with a case of endocarditis. The cells 



