990 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



where hydrogen sulfide occurs. Accord- 

 ing to Bavendamm (Die farblosen u. 

 roten Schwefclbakt., Pflanzenforschung, 

 Heft 2, 1924, 107) also found in sea water. 



3. Thiothrix tenuissima Winogradsky. 

 (Beitr. z. Morph. u. Physiol, d. Bact., I, 

 Schwefelbacterien, 1888, 40; Thiothrix 

 minutissima Uphof, Arch. f. Hydrobiol., 

 18, 1927, 77.) From Latin tenuis, diminu- 

 tive, very slender. 



Filaments less than 0.5 micron in 

 diameter, usually in dense masses. 



Habitat: Fresh water environments 

 where hydrogen sulfide occurs. 



4. Thiothrix voukii Klas. (Arch. f. 

 Protistenk., 88, 1936, 123.) Named for 

 Vouk, a Russian scientist. 



Filaments 15 to 30, most frequently 17 

 microns in diameter, of rather uniform 

 thickness. Segments visible without 

 special treatment. Segments generally 

 somewhat longer than wide, rareh 

 square, occasionally barrel-shaped. 

 Length of segments 15 to 30, mostly 19 

 to 23 microns. Motile segments not yet 

 observed. 



Apart from the lack of motilitj'. this 

 species closely resembles the motile 

 Beggiatoa mirabilis. 



Source: Found in effluent of sulfur 

 springs at seashore near Split, Jugo- 

 slavia. So far reported only once. 



Habitat: Marine environments con- 

 taining hydrogen sulfide. 



5. Thiothrix longiarticulata Klas. 



(Arch. f. Protisteiik., 88, 1936, 126.) 

 From Latin longus, long and articulatus, 

 jointed. 



Filaments 3.3 to 6.6, most frequently 

 4.2 microns in diameter, of uniform 

 thickness. Occur in dense, felted 

 masses. Segments long, measuring 19 



to 33, mostly 26 microns in length. Sul- 

 fur droplets usually absent in the prox- 

 imity of cross-walls. Motile segments 

 not yet reported. 



Source : Found in effluent of sulfur 

 springs at seashore near Split, .Jugo- 

 slavia. So far reported only once. 



Habitat: Marine environments con- 

 taining hydrogen sulfide. 



6. Thiothrix annuIataMolisch. (Cent. 

 f. Bakt., II Abt., 33, 1912, 58.) From 

 Latin annulatus, ringed. 



Filaments 3 to 4, occasionally up to 5 

 microns in diameter, thinner at base 

 (2 microns) and at tip (1.8 microns). 

 Segments only about 1 micron in length. 

 Often found with narrow bands which 

 are free of sulfur, thus giving a ringed 

 appearance to the filaments. Old fila- 

 ments may show spacial thickening and 

 distortion, but this is not characteristic 

 for the species. 



Habitat : Marine environments contain- 

 ing hydrogen sulfide; frequently on de- 

 caying algae. 



7. Thiothrix marina Molisch. (Cent, 

 f. Bakt., II Abt., S3, 1912, 58.) From 

 Latin marinus, pertaining to the sea. 



Filaments about 1 (0.8 to 1.3) micron 

 in diameter, of rather uniform thick- 

 ness. L^sually in felted masses. 



Resembles Thiothrix tenuis. Since 

 the latter has been reported from marine 

 environments (Bavendamm, Die far- 

 blosen u. roten Schwefelbakterien, Pflan- 

 zenforschung, Heft 2, 192'4, 107), Thio- 

 thrix marina maj' not be an independent 

 species, but identical with Thiothrix 

 tenuis. 



Habitat : Marine (?) environments con- 

 taining hydrogen sulfide; frequently on 

 decaying algae. 



Genus II. 



iatoa Trevisan. 



(Prospetto della Flora Euganea, 1842, 56.) Named for the Vicenza physician, 

 F. S. Beggiato. 



Filamentous, motile, segmented organisms, occurring singly or in wliitc to creamy 

 felted masses in which the separate filaments retain their individuality. Not at- 



