cent proteose peptoue + 2 per cent KNO3) : Circular, smooth, entire, raised to convex, butyrous, glistening, opaque with a slightly transparent margin which is less colored, orange-brown, orange-red or orange-yellow. Agar slant (24 per cent salt + 1 per cent peptone + 2 per cent KNO3): Growth moderate, filiform, raised to convex, glisten- ing, smooth, butyrous, opaque, orange-red. Broth (24 per cent salt + 1 per cent pep- tone) : Turbid; orange-red pellicle; slightly viscous sediment. Asparagine broth (24 per cent salt + 1 per cent asparagine): Turbid. Indole not produced. Acid from glucose, fructose, mannose and glycerol ; slight acid from xylose and salicin (tests made in 24 per cent salt + 1 per cent peptone + 1 per cent carbohydrate during 3 weeks). Starch not hj-drolyzed. Nitrites rapidly produced from nitrates; gas is produced (tests made in 24 per cent salt + 1 per cent peptone + 2 per cent KNO3). Aerobic. Optimum temperature, 30° C. Salt tolerance: Halophilic, obligate; grows in 18 per cent to saturated salt solu- tions; slight growth in 15 per cent salt. Distinctive character: The pigment pro- duces a blue color with concentrated sul- furic acid, thus suggesting a carotenoid; it is very soluble in pyridine, less soluble in methanol, ethanol and chloroform, slightly soluble in acetone, very slightly so in ben- zol and insoluble in xylene and petroleum ether. Source: Isolated from Dead Sea water. Habitat: Salt lakes.
5. Halobacteriuin trapanicum (Petter, 1931) Elazari-Volcani, 1940. (Bacterium trapanicum Petter, Proc. Kon. Acad. v. Wetensch. Amsterdam, S4, 1931, 1417; also see Petter, Over roode en andere bacterien van gezouten visch. Thesis, Utrecht, 1932; Flavohacterium (Halobacterium) trapanicum Elazari-Volcani, Studies on the Microflora of the Dead Sea. Thesis, Hebrew Univ., Jerusalem, 1940, V and 59.) tra.pa'ni.cum. M.L. adj. trapanicus per- taining to "Trapani" salt. Rods, 0.6 by 1.5 to 3.5 microns. The length and shape of the cells may vary greatly with the medium: in Dead Sea water + 1 per cent proteose peptone, the cells occur singly and are 0.45 to 0.55 by 1.5 to 4.8 microns with occasional rods measuring 8.0 to 16.0 mi- crons in length; in 24 per cent salt + 1 per cent peptone, the short rods predominate; in 24 per cent salt + 1 per cent peptone + 2 per cent KNO3 agar, the cells are ovoid, measuring 1.0 to 1.5 microns in diameter. Non-motile. Gram-negative. Gelatin stab (18 per cent salt -f 1 per cent peptone -1- 30 per cent gelatin) : Surface growth. No liquefaction (2 months). Agar colonies (24 per cent salt + 1 per cent proteose peptone + 2 per cent KNO3) : Small (1 to 2 mm in diameter), circular, smooth, entire, convex, glistening, trans- parent, light orange or slightly colorless. Agar slant (24 per cent salt -f 1 per cent peptone + 2 per cent KNO3): Growth moderate, filiform, raised, glistening, smooth, opaque or slightly transparent, light orange. Broth (Dead Sea water -f 1 per cent pep- tone) : Orange-rose pellicle; turbid; orange sediment. In 24 per cent salt + 1 per cent peptone: orange -rose ring; turbid; orange sediment. Asparagine broth (24 per cent salt + 1 per cent asparagine) : Moderately turbid. Indole not produced. No acid from arabinose, xylose, glucose, fructose, galactose, mannose, lactose, su- crose, maltose, raffinose, inulin, dextrin, glycerol, mannitol or salicin (tests made in 24 per cent salt + 1 per cent peptone + 1 per cent carbohydrate during 3 weeks). Starch not hydrolyzed. Nitrites rapidly produced from nitrates; gas is produced (tests made in 24 per cent salt + 1 per cent peptone + 2 per cent KNO3). Catalase-positive. Aerobic. Optimum temperature, between 30° and 37° C. Salt tolerance: Halophilic, obligate; grows in 18 per cent to saturated salt solu- tions ; slight growth in 15 per cent salt. Distinctive character: The pigment pro-
