spiral formation; spirals long and open, not compact. Gelatin: P^locculent growth. No aerial mycelium. Rapid liquefaction. No pigment production. Agar: Brown-colored growth covered with tiny patches of ivorj^-colored aerial mj^ce- lium. Synthetic agar: Same as on glucose agar. Potato: Abundant brownish growth with white to mouse-gray aerial mycelium. Glucose agar: Thin yellowish growth, later turning reddish brown; no soluble pig- ment; light gray to mouse-gray mj'celium with white edge. Tj'pical odor of strepto- myces . Strong proteolytic enzymes acting on casein and gelatin. Strong diastatic action; no sugar or dex- trin left in 1 per cent starch solution after a few days. Limited reduction of nitrate. Antagonistic properties: Certain strains produce an antibiotic designated as cacao- mycetin. Source: Three strains were isolated from cacao beans in Nigeria. There were slight differences among the three strains; the above description is of Strain I. Habitat: The cacao bean so far as known. 90. Streptomyces marinus (Humm and Shepard, 1946) Waksman, comb. nov. (Acti- nomyces marinus Humm and Shepard, Duke Univ. Marine Sta. Bull., 3, 1946, 77.) ma.ri'nus. L. adj. marinus marine, of the sea. Vegetative growth: Mycelium sparingly branched, dense, entangled. Growth on agar moderately rapid, reaching a diameter of one cm or more after about ten days. My- celium frequently forms concentric rings in response to alternate periods of light and darkness. No soluble pigments. Aerial mycelium: White; conidia medium gray to dark gray. Aerial hyphae somewhat irregular in diameter, 0.8 to 1.4 microns. Conidia spherical to ellipsoidal, 0.8 to 1.2 microns in diameter, in chains, sometimes forming loose spirals. Conidia typically appear after three days as a dark gray area in center of each colony. Gelatin: Growth arborescent. Stratiform liquefaction, beginning after about ten days at 20° to 23° C. Broth: Strong white pellicle. White tufts may develop at sides of tube beneath sur- face of liquid. Milk: Alkaline within one week; com- pletely peptonized, usually within one month at 25° to 30° C. Indole not produced. Indigotin not pro- duced from indole. Hydrogen sulfide vigorously produced. Acid from galactose, glucose, fructose, mannose, cellobiose, lactose, maltose, su- crose and glycerol. Arabinose, xylose, rham- nose and sorbitol utilized without acid production. No growth in raffinose, salicin, inulin, dulcitol, inositol, ethyl alcohol or ethylene glycol. Acetylmethylcarbinol not produced. Starch vigorously hydrolyzed. Cellulo.se not hydrolyzed. Chitin and alginic acid are attacked. Seaweed gells: Agar slowly digested; softened, not liquefied. Growth on agar in culture dish surrounded by rather wide, gently sloping depression. Gelase field rela- tively wide with distinct margin. Irish moss and Hypnea gels also slowly digested. Acetic, citric, lactic, propionic, succinic and iso-valeric acids utilized. Butyric, gluconic, maleic, malonic and oxalic acids not utilized. Aspartic acid, cystine, glutamic acid, glycine, 1-leucine and tyrosine utilized as sources of both nitrogen and carbon, dl- Alanine and d-arginine utilized only as nitrogen sources. Creatine and dl-/3-phenyl- alanine not utilized. Glucosamine-HCl utilized as source of nitrogen and carbon. Ammonia, nitrite or nitrate utilized as nitrogen sources. Ammonia produced from nitrate, asparagine, peptone and glutamic acid. Urea used as nitrogen source with production of small amounts of ammonia. Nitrites usually not produced from ni- trates. In some media, slight nitrite is pro- duced after ten days' incubation, especially if glucose is present. Catalase-positive. Aerobic. Optimum temperature, between 25° and 30° C. Good growth in media prepared with dis-
