Note: Krassilnikov (Guide to the Bac- teria and Actinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1949, 123) states that probably a considerable number of previ- ously described species placed in the genus Micrococcus really belong in the genus My- cococcus as he has described it. Inasmuch as Hucker (personal communication, 1955) has always felt that the two species of red micro- cocci recognized by him (Hucker, N. Y. State Exp. Sta. Tech. Bull. 135, 1938, 33 pp.) as Micrococcus cinnabar eus Fliigge and as M. rhodochrous Migula were not typical micro- cocci, further studies of cultures of these coral-red to cinnabar-red species have been made by Dr. Ruth Gordon and by Dr. A. G. Lochhead. These investigators are in agree- ment that these species may well be myco- cocci or nocardias. For this reason the descriptions of the two species under consid- eration have been removed from the section in which micrococci are described and are given in this note. It is of interest in this connection that Hucker (N. Y. State Exp. Sta. Tech. Bull. 102, 1924, 26) lists nearly a dozen named and described (sometimes very poorly) species of red micrococci that may be identical with one or the other of the two species described below. 1. Micrococcus cinnabareus Fliigge, 1886. (Die Mikroorganismen, 2 Aufl., 1886, 174.) cin.na.ba're.us. Gr. noun cinnahari cin- nabar, vermilion; M.L. adj. cinnabareus of the color of vermilion. Spheres, 1.0 micron in diameter, occur- ring singly and in pairs. Non-motile. Gram-variable. Gelatin colonies: Small, circular, bright red, becoming cinnabar-red. Gelatin stab: Thick, raised, rose- to cin- nabar-red growth on surface. No liquefac- tion. White colonies along stab. Agar slant: A carmine-red streak. Slow growth. Broth: Turbid. Litmus milk: Slightly alkaline to slightly acid. Potato: Slowl}^ developing vermilion- red streak. Indole not produced. Small amount of acid from sugars. Starch not hydrolyzed. Nitrites produced from nitrates. Does not utilize NH4H2PO4 as a source of nitrogen. Aerobic. Optimum temperature, 25° C. Saprophytic. Source: Found as contamination of cul- tures. Habitat: Usually found as a dust con- tamination. 2. Micrococcus rhodochrous (Zopf, 1891) Migula, 1900. (Rhodococcus rhodochrous Zopf, Berichte d. deutsch. bot. Gesellsch., 9, 1891, 22; Migula, Syst. d. Bakt., 2, 1900, 162.) rho.do'chro.us. Gr. noun rhodum the rose; Gr. noun chroa color, complexion; M.L. adj. rhodochrous rose-colored. Spheres, 0.5 to 1.0 micron in diameter, occurring singly. Non-motile. Gram-vari- able. Gelatin colonies: Small, circular, glisten- ing, raised, entire, dark, reddish brown. Gelatin stab: Dark, carmine-red, dry sur- face growth. Slight growth in stab. No liq- uefaction. Agar slant: Carmine-red streak, becom- ing brick-red in color. Broth: Thick, rose-red pellicle with red, flocculent sediment. Litmus milk: Slightl}^ alkaline. Potato: Carmine-red streak. Acid from glucose. No acid from lactose, sucrose, glycerol or mannitol (Hucker, 1923, retest of original culture). Nitrites produced from nitrates (Hucker, 1923, retest of original culture). Aerobic. Optimum temperature, 25° C. Saprophytic. Comments: In the description of this or- ganism given by Migula, which is taken from Zopf's original description, emphasis is laid on the arrangement of the cells in tetrads or occasionallj' as diplococci. Mention is made of short chains, but again emphasis is laid on the fact that these are not formed by division in planes parallel with each other, as are the chains of streptococci, but rather by an accidental rearrangement of tetrads, the cells dividing in two planes perpendicu-
