B. Trichomes more than 2.0 microns in diameter. 7. Vitreoscilla moniliformis. II. Trichomes more than 2.5 microns in diameter. Not cultivated in pure culture. A. Trichomes 4.0 microns in diameter. Sluggishly motile. 8. Vitreoscilla conica. B. Trichomes more than 4.0 microns in diameter. Actively motile. 9. Vitreoscilla major. 1. Vitreoscilla beggiatoides Prings- heim, 1949. (Bact. Rev., 13, 1949, 70; also see Jour. Gen. Microbiol., 5, 1951, 127.) beg.gi.a.to.i'des. M.L. fem.n. Beggiatoa a generic name; Gr. noun eidus shape, form; M.L. adj. beggiatoides Beggiatoa-ike. Cylindrical trichomes measuring about 2 microns in diameter, sometimes more or less; length almost unrestricted, but under less favorable environments the trichomes may be as short as 10 microns. The tri- chomes are composed of cylindrical units showing constrictions which indicate the locations of cell wall primordia. Motile. Gram-negative. Gelatin: No liquefaction. Agar: Growth in curls, spirals and waves with loose ends. Liquid media: Growth in trichomes of low optical refraction. Casein not digested. Source : Isolated from a ditch with decay- ing water weeds on Coldham Common, Cambridge, where it occurred together with Sphaerotilus discophorus, Beggiatoa alba and many other organisms. Habitat: Found in quiet waters rich in organic material and with black mud on the bottom. 2. Vitreoscilla stercoraria Pringsheim, 1951. (Jour. Gen. Microbiol., 5, 1951, 136.) ster.co.ra'ri.a. L. adj. stercorari^is per- taining to dung. Trichomes 1.2 to 1.5 microns in diameter, varying in length, measuring up to 100 mi- crons. The trichomes may be composed of rods of considerable length (12 microns and more) or of cells which are not much longer than they are wide. Above a certain length the trichomes rarely remain straight but bend irregularly forming aggregates like curled hair. Motility is hesitant and slow. Gram-negative. Gelatin: No liquefaction. Agar: Colonies are very dense and are connected by a fine network; regular spirals are formed. On rich media the colonies be- come thicker and, after some time, yellow- ish to translucent owing to autolysis of cells. Liquid media: Growth at first filamentous and loose; later becomes flocculent. Casein not digested. Distinctive character: Dense colonies on agar connected by a fine network. Source : Isolated from dung. Habitat: Found in decomposing organic material. 3. Vitreoscilla filiformis Pringsheim, 1951. (Jour. Gen. Microbiol., 5, 1951, 130.) fi.li.for'mis. L. nomx filum a thread; L. noun forma shape; M.L. adj. fliliformis thread-shaped. Cylindrical trichomes, 1.2 microns in diameter, of unlimited length, although short trichomes are regularly present. Tri- chomes pronouncedly more elastic and of greater tensile strength than are those of the other species in this genus. Both long and short trichomes exhibit an active glid- ing and swinging of the free ends. Gram- negative. Gelatin: No liquefaction. Agar: Growth occurs in delicate, more or less circular whirls and loops. Liquid media: Growth occurs near the bottom or in tufts on the walls of the con- taining Casein not digested. Distinctive characters : Trichomes slender and elastic. Growth on agar is in the form of neatly rounded arches and loops as in certain species of Oscillatoria. Source: Isolated from a crude culture consisting of a grain of wheat covered with soil and water from the pond in the Cam- bridge Botanic Garden.
