Page:Bergey's manual of determinative bacteriology.djvu/293

 The bands may reach a length of 700 microns.

Source : Found in Germany in ponds where Chara sp. was growing; also found by Beger (1954) in decomposing plant materials on the surface of bottom mud along with Beggiatoa, Thiospira, Zoogloea and similar types of bacteria.

Habitat: Presumably widely distributed in fresh-water ponds.

Pe.lo.ne'ma. Gr. adj. pellos or pelos dark-colored; Gr. noun neina filament; M.L. neut.n. Pelonema dark-colored filament.

Long, unbranching trichomes, occurring singly, which are either straight or spirally twisted. The trichomes are enclosed in a very thin, delicate sheath. Non-motile, but may become motile. Within the trichomes are Cylindrical, colorless cells which contain one or several to many false vacuoles which emit a reddish gleam of light. Found on the surfaces of ponds and lakes which contain decomposing algae and which are poorly aerated.

The type species is Pelonema tenue Lauterborn.

I. Cells contain a single false vacuole.


 * A. Cells 8 to 12 microns long; trichomes are straight and attain a length of up to 300 microns.


 * B. Cells 4 to 6 microns long; trichomes are straight and are 200 or more microns long.

II. Cells contain several to many false vacuoles.


 * A. Trichomes are straight, measuring up to 500 microns in length.


 * B. Trichomes are spirally twisted, reaching a length of 40 to 160 microns.

1. Pelonema tenue Lauterborn, 1915. (Verhandl. Naturhist.- med. Verein z. Heidelberg, N.F. 13, 1915, 408.)

te'nu.e. L. adj. tenuis slender.

Straight trichomes, up to 300 microns long, which may become motile when the water in which they are growing is low in oxygen content. Cells are 2 by 8 to 12 microns. Each cell contains a single false vacuole which nearly fills the cell; the vacuole is irregular in shape and emits but a small reddish gleam of light.

Source: From pools in the Rheinebene, Germany, where Chara was growing.

Habitat: Presumably widely distributed in fresh-water ponds and lakes which contain decomposing algae.

2. Pelonema hyalinum Koppe, 1923. (Pelonema hyalina (sic) Koppe, Archiv. f. Hydrobiologie, 14, 1923, 625.)

hy. a. li'num. Gr. adj. hyalinus of crystal, glass; M.L. adj. hyalinus hyaline.

Straight trichomes which measure 200 or more microns in length. The cells, 2 by 4 to 6 microns, contain a single false vacuole which is quite large and slightly refractive; the vacuole is rectangular in shape and has rounded edges.

Source: From water from Little Plöner Lake, Schleswig-Holstein, Germany.

Habitat: Found in the upper algae-containing layers of deep fresh-water lakes.

3. 'Pelonema pseudovacuolatum Lauterborn, 1915. (Verhandl. Naturhist.- med. Verein z. Heidelberg, N.F. 13, 1915, 408.)

pseu.do. va.cu.o.Ia'tum. Gr. adj. pseudes false; L. adj. vacuus empty; M. L. noun vacuola a vacuole; M.L. adj. pseudovacuolatus having false vacuoles.

Straight trichomes measuring up to 500