Straight or curved rods, with rounded ends, which show a marked pleomorphism ; fila- mentous and branching forms occur. Motile and non-motile species. Gram-negative. May- or may not require enriched culture media. Usually ferment glucose, rarely lactose or su- crose. Nitrites not produced from nitrates. Gas may or may not be produced in peptone media. Anaerobic. Found in the alimentary and urogenital tracts of man and other animals; also found in various gangrenous or purulent infections in man. The type species is Sphaerophonis necrophorus (Fliigge) Prevot. Keij to the species of genus Sphaerophorus. I. Non-motile. Sub-genus Sphaerophorus Prevot (Ann. Inst. Past., 60, 1938, 297). A. Gas produced in culture media. 1. Do not require serum or ascitic fluid for growth. a. Gelatin not liquefied. 1. Sphaerophorus necrophorus. 2. Sphaerophorus inaequalis. 3. Sphaerophorus varius. 4. Sphaerophorus siccus. 5. Sphaerophorus necroticus. 6. Sphaerophorus necrogenes. 7. Sphaerophorus ridiculosus. aa. Gelatin liquefied slowly. 8. Sphaerophorus gulosus. 2. Require serum or ascitic fluid for growth. 9. Sphaerophorus mortiferus. 10. Sphaerophorus gonidiaformans . 11. Sphaerophorus freundii . 12. Sphaerophorus pyogenes. B. No gas produced in culture media. 1. Do not require serum or ascitic fluid for growth, a. Slow coagulation of milk. 13. Sphaerophorus infiuenzaejormis. aa. No coagulation of milk. 14. Sphaerophorus fioccosus. After the manuscript was prepared in this way, it was discovered that Sphaerophorus Prevot is an illegitimate homonym of Sphaerophorus Persoon (Einige Bemerkungen iiber der Flech- ten. Neue Annalen d. Bot., edited by Dr. Paulus Usteri, 7, 1794, 1-32). Persoon included two species of lichens in this genus, and the name continues in use among botanists (see for example. Fink, Lichen Flora of the United States, 1935, 78). Dr. Prevot 's attention has been called to this unfortunate situation in order that he may make such adjustments in nomenclature as he feels are desirable. The problem of adjusting the nomenclature is com- plicated by the fact that Thj0tta, in Lahelle and Thj0tta (Acta Path, et Microbiol. Scand., 22, 1945, 310), without noting the previous proposal oi Sphaerophorus Prevot, 1938, has pro- posed Necrohacterium as the name of the genus in which he would place the necrosis bacillus. However, no use is made of a scientific name for the necrosis bacillus in the paper by Lahelle and Thj0tta. Neither is the binomial Necrohacterium necrophorum used by Lahelle {Necro- hacterium, Thesis, Univ. Oslo, 1947, 166), this binomial appearing first as Necrohacterium necrophorus (sic) in Jonsen and Thj0tta, Acta Path, et Microbiol. Scand., 25, 1948, 698. It is unfortunate that so many authors fail to observe conventional requirements established in order to produce stability in nomenclature. If the definition given above for Sphaero- phorus is accepted, then it would appear that the correct name for the necrosis bacillus is Necrohacterium necrophorum. Some may feel that this name should be ascribed to Thj0tta 1945 by implication although this binomial was not actually published until 1948 by Jonsen and Thj0tta. — Editors
