1. Bactoscilla flexibilis Pringsheim, 1949. (Pringsheim, Bact. Rev., 13, 1949, 72; Bactoscilla tnobilis Pringsheim, Jour. Gen. Microbiol., 5, 1951, 144.) flex.i.bil'is. L. adj. flexibilis flexible. Short, slender trichomes, about 0.4 to 0.5 micron in diameter, composed of a num- ber of slender, rod-shaped cells apparently separated bj^ empty interspaces. The tri- chomes bend slowly and pronouncedly at the joints, the individual cells remaining straight. Motile. Gram-negative. Relationship to other species: Structur- all}^ comparable to Ldneola articulata which is, however, motile by means of peritri- chous flagella. Source: Found in scum composed mainly of Myjophyceac from the outlet of the 'Clay Pond' near the Freshwater Biological Asso- ciation laboratorj^ at Wraj^ Castle, Amble- side, later in the surface film of water over black mud from Flatford Mill Field Centre and a third time in mixed material from a duck pond near Colchester, all in England. Habitat: Found in fresh water containing decomposing organic material. Genus III. Microscilla Pringsheim, 1951. (Microscilla Pringsheim {nonien nudum), Bact. Rev., 13, 1949, 72; Pringsheim, Jour. Gen. Microbiol., 5, 1951, 127 and 140.) Micros. cil'la. Gr. adj. micrus small; L. noun osrillum a swing; M.L. fem.n. Microscilla the small oscillator. Slender trichomes without perceptible septation. Motile by means of active, gliding move- ments. Gram-negative. Reproduction is by division into relatively long daughter trichomes. Found on fresh-water and marine algae. The type species is Microscilla marina Pringsheim. Key to the species of genus Microscilla. I. From salt water. Sea water or artificial sea water required for growth. 1. Microscilla marina. II. From fresh water. Sea water or artificial sea water not required for growth. A. Trichomes possess a free-swinging end. 2. Microscilla flagellum. B. Trichomes do not possess a free-swinging end. 3. Microscilla ngilis. 1. Microscilla marina Pringsheim, 1951. (Vitreoscilla marina Pringsheim (nomen nudum), Bact. Rev., 13, 1949, 72; Prings- heim, Jour. Gen. Microbiol., 5, 1951, 140.) ma.ri'na. L. adj. marinus pertaining to the sea, marine. Slender trichomes, 0.5 to 0.6 by up to 100 microns, apparently without septation. The gliding movement, active and quick, particularly in young cultures from liquid media, is not associated with rotation but with much bending and waving. Gram-nega- tive. Sea water is required for growth. Sea-water agar: Growth barely percepti- ble as a grayish veil. Microscopically the veil is seen to consist of a delicate network of widely separated trichomes forming loops and meshes. On a medium composed of sodium acetate (0.1 per cent), Difco yeast-extract (0.1 per cent), Bactotryptone (0.1 per cent), soil extract (5 per cent), artificial sea water (half concentrated) and agar (1 per cent) and neutralized with calcium carbonate, a thick, peach- to orange-colored layer is produced after 4 days; after one week, the rich orange growth disappears due to au- tolysis of the cells; smaller growths keep their filamentous appearance for several weeks. Liquid media: Growth occurs in floating bundles of more or less parallel trichomes gliding along one another. Source: Isolated from fragments of Schizo- nema (diatoms) filaments from Brighton, Sussex, England. Habitat: Found on marine algae.
