7. Vitreoscilla moniliformis Prings- heim, 1949. (Bact. Rev., 13, 1949, 72; also see Jour. Gen. Microbiol., 5, 1951, 132.) mo.ni.li.for'mis. L. noun inonile a neck- lace; L. nonn forma shape; M.L. adj. monili- formis necklace-like. On plates the trichomes are in the form of relatively large, streptococcus-like chains. In mounted preparations the tri- chomes measure up to 150 microns in length, although generally they are only 30 microns long. The trichomes are composed of a lim- ited number of rod-shaped sections with rounded ends which often appear to be sepa- rated by short gaps; the trichomes, however, move as a whole. The sausage-shaped sec- tions are mostly j!^ to 2.5 microns wide and are not very regular in form, often inflated to a diameter of 2.8 to 3.0 microns, some- times only a little longer than they are wide; sometimes they measure 15 microns in length and are elongated and cylindrical. The cells tend to separate from each other, and units of 4 to 5 cells are often found. Long before division, the cells are marked by constriction. Motility not very active. Gram-negative. Gelatin: No liquefaction. Agar: Growth rather diffuse; the edges, particularly on less rich media, are com- posed of tongue-like processes while rounded, twisted areas may be seen in the interior of large colonies. Liquid media: Markedly turbid; later, a sediment is formed. Casein not digested. Distinctive characters: Growth more rapid and abundant than with the other species of this genus. Not fastidious in food requirements. Source: Isolated by Dr. C. F. Robinow from cow dung. Habitat: Found in decomposing organic materials. 8. Vitreoscilla conica Pringsheim, 1951. (Jour. Gen. Microbiol., 5, 1951, 139.) con'i.ca. Gr. adj. conicus conical. Trichomes about 4 microns wide and gen- erally 20 to 50 microns in length. The cells are slightly barrel-shaped and are filled with refractive pseudo-granules. The terminal cell is often longer than the other cells and is attenuated near the tip. Not actively motile. Gram-negative. Comment: This species has not been grown in pure culture. Source: Described from mud from a pond at Du Klip Vlei, Cape Flates, Cape Prov- ince, South Africa, which had dried out during the dry season and which was again moistened in the laboratory. Habitat: Mud. 9. Vitreoscilla major Pringsheim, 1951. (Jour. Gen. Microbiol., 5, 1951, 138.) ma'jor. L. comp.adj. major larger. Trichomes relatively long and colorless, 6 to 7 microns in diameter, composed of cells whose length (5 microns) is slightly less than their width. A few refractive gran- ules are found near the septa. The terminal cells are in the form of flattened hemi- spheres. As observed from the tip, the tri- chomes rotate clockwise. Gram-negative. Comment: This species has not been grown in pure culture. Relationship to other species: Morpho- logically similar to the species in the genus Thiothrix from which, however, it is dis- tinguished by its continuous, active bending and twisting. Source: Found in half -dried mud from a ditch at Cherry Hinton, Cambridge, Eng- land. Habitat: Mud. Genus II. Bactoscilla Pringsheim, 1949. (Bact. Rev., 13, 1949, 72; also see Jour. Gen. Microbiol., 5, 1951, 144.) Bac.tos.cil'la. Bact- probably intended as a part of the stem of the Gr. noun bactrum a staff, rod; L. noun oscillum a swing; M.L. fem.n. Bactoscilla oscillating rod. Very slender trichomes composed of rod-shaped cells apparently separated by empty interspaces. Motile by means of a gliding movement. There is a slow, pronounced bending of the trichomes at the joints, the individual cells remaining rigid. Gram-negative. Found in fresh water containing decomposing organic matter. The type species is Bactoscilla flexibilis Pringsheim.
