orange, depending on the medium; cells 0.3 to 0.9 micron in diameter. After one j^ear of cultivation in peptone broth, strains Nos. 43 and 45 dissociated to form mycobacterial strains which were closely related to each other. Cells were rod- shaped, 0.8 by 0.5 to 2.5 microns, curving and branching, changing to cocci in 3 to 5 days. Enlarged cells were formed on cer- tain media. These showed no differences in fermentative capacity as compared with the original culture. Krassilnikov regards these organisms as closely related to Mycobac- terium brevicale on the basis of appearance of cells, pigmentation of colonies and physio- logical properties. Krassilnikov (loc. cit.) recognizes as a subspecies Mycococcus tetra- genus. Source: Isolated from soil at Yershovo Station, Russia. Habitat: Infrequently found in soil. 2a. Mycococcus ruber subsp. tetragenus Krassilnikov, 1938. (Ray Fungi and Related Organisms, Izd. Akad. Nauk, U.S.S.R., Moskau, 1938, 121.) tet.ra'ge.nus. Gr. pref. tetra four; Gr. v. gennaio to produce; M.L. adj. tetragenus produced in fours. Original description supplemented by material from Krassilnikov (Guide to the Actinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 126). Cells coccoid, occurring in tetrads formed by the multiplication of two different branches; occasionally combined into parallel chains. Both types are consistently found on synthetic agar. Colonies: Red; slightly enlarged; weak shine. Physiological and cultural characteristics are, in general, not different from those of Mycococcus ruber. Comment: Krassilnikov regards this or- ganism as a form of Mycococcus ruber. Two strains have been isolated. Source: Isolated from soil. Habitat: Infrequently found in soil. 3. Mycococcus capsulatus Krassilni- kov, 1938. (Microbiologia (Russian), 7, Part 1, 1938, 349.) cap.su.la'tus. L. noun capsula a small chest; M.L. adj. capsulatus encapsulated. Original description supplemented bj^ material from Krassilnikov (Guide to the Actinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 127). Cells rounded, irregular in size, 0.7 to 1.0 micron in diameter, frequently occurring in short chains of 3 to 7 cells. Cells surrounded by a thick, slimy capsule. Chains sometimes form side branches. Not acid-fast. Gram- positive. Colonies : Rose or pale rose, slimy, spread- ing. No soluble pigment. Physiological properties and fermentative capacity are not different from those of Mycococcus ruber. Comment : One of the two strains isolated, No. 53, dissociated into strains with smooth colonies and rod-shaped cells, 0.7 by 1.5 to 5.5 microns, without a slimy capsule. Fermentative capacity no different from that of the original culture. Krassilnikov regards this strain as closely related to Mycobacterium planum on the basis of its cultural, morphological and physiological properties. Krassilnikov (loc. cit.) regards this or- ganism as a subspecies of Mycococcus muco- sus. Source: Isolated from soil. Habitat: Infrequently found in soil. 3a. Mycococcus capsulatus subsp. niucosus Krassilnikov, 1938. (Ray Fungi and Related Organisms, Izd. Akad. Nauk, U.S.S.R., Moskau, 1938, 349.) mu.co'sus. L. adj. mucosas slimy, mu- cous. Original description supplemented by material from Krassilnikov (Guide to the Actinomycetes, Izd. Akad. Nauk, U.S.S.R., Moskau, 1941, 127). Cells occur in tetrads in one plane, occa- sionally forming short, parallel chains and joining chains, surrounded by a thin, slimy capsule. There are also cells which form individual cases of branching rods. Resting cells are found. Cultural and physiological characters are not different from those of Mycococcus cap- sulatus. Comment: Krassilnikov regards this or-
