Page:Bergey's manual of determinative bacteriology.djvu/86

 may be found as elements in chains for the greater part composed of normal individuals.

Habitat: Mud and stagnant water containing rather high concentrations of hydrogen sulfide and exposed to light; sulfur springs.

Illustrations: Szafer, op. cit., 1910, Pl. VI, fig. 5; Perfiliev, Jour. Microbiol. (Russian), 1, 1914, Pl. II, fig. 1, 5-12; Lauterborn, op. cit., 1915, Pl. III, fig. 33.

2. Pelodictyon aggregatum Perfiliev, 1914. (Aphanothece luteola Schmidle, Beihefte Botan. Cent., 10, 1901, 179; Perfiliev, Jour. Microbiol. (Russian), 1, 1914, 197.)

ag.gre.ga′tum. L. part. adj. aggregatus added to a flock, aggregated, clumped.

Cells usually rod-shaped, about 1 to 1.5 by 2 to 4 microns, often vacuolated, producing slime capsules and united into irregularly shaped, three-dimensional colonies in which the cells are more or less tightly packed without orderly arrangement. Colonies may attain a size of up to 1 mm; frequently they are not fully compact but contain less dense areas or appear perforated, thus forming transition stages to Pelodictyon clathratiforme. Non-motile.

Color: Yellowish green.

Abnormal cell forms (involution forms) usually in the shape of elongated and curved, forked or club-shaped and swollen rods, occasionally suggesting branching at extremities.

Source: Isolated from sulfureted water in Europe; also reported by Button and Juday (Ecology, 25, 1944, 277) from Scaffold Lake, Wisconsin.

Habitat: Mud and stagnant water containing rather high concentrations of hydrogen sulfide and exposed to light; sulfur springs.

Illustrations: Perfiliev, ibid., Pl. II, fig. 2; Lauterborn, Verhandl. naturhistor.-medizin. Vereins, Heidelberg, N.F. 13, 1915, Pl. Ill, fig. 29-31.

3. Pelodictyon parallelum (Szafer, 1910) Perfiliev, 1914. ('Aphanothece parallela Szafer, Bull. Acad. Sci., Cracovie, Sér. B, 3, 1910, 163; Perfiliev, Jour. Microbiol. (Russian), 1, 1914, 198.)

pa.ral.le′lum. Gr. adj. parallelus parallel. Cells rather small, spherical to ovoid, or even rod-shaped; about 0.5 to 1 by 1 to 3 microns, occurring in chains and forming flat, plate-like, two-dimensional aggregates in which the chains are arranged as parallel strands. Non-motile.

Color: Yellowish green.

Abnormal cell forms not specifically mentioned, but likely to occur and to resemble those of other species.

This species may well be a special growth-form of Chlorobium limicola.

Habitat: Mud and stagnant water containing rather high concentrations of hydrogen sulfide and exposed to light; sulfur springs.

Illustrations: Szafer, op. cit., 1910, Pl. VI, fig. 7; Perfiliev, op. cit., 1914, Pl. II, fig. 2.

Genus III. Clathrochloris Geitler, 1925. (Geitler, in Pascher, Die Süsswasserflora Deutschlands, Österreichs und der Schweiz, Jena, 12, 1925, 457.)

Clath.ro.chlo′ris. L. pl. noun clathri lattice; Gr. adj. chlorus green; M.L. fem. n. Clathrochloris green lattice. Sulfur green bacteria of small size, generally spherical and arranged in chains which are united into loose, trellis-shaped aggregates, somewhat similar to those of Pelodictyon clathratiforme and Pelodictyon aggregatum. Cells usually contain sulfur globules. Color is yellowish green. Non-motile.

The type species is Clathrochloris sulphurica (Szafer) Geitler.

1. Clathrochloris sulphurica (Szafer, 1910) Geitler, 1925. (Aphanothece sulphurica Szafer, Bull. Acad. Sci., Cracovie, Sér. B, 3, 1910, 162; Geitler, Die Süsswasserflora Deutschlands, Österreichs und der Schweiz, Jena, 12, 1925, 457.)