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MANUAL OP DETERMINATIVE BACTERIOLOGY 



species of Beggialoa in a common slieath. This occurrence of two distinct species of 

 Beggiatoa in a common sheath makes the genus a doubtful taxonomic entity. 

 The type species is Thioploca schmidlei Lauterborn. 



Key to the species of genus Thioploca. 



I. Filaments in a common sheath of fairly uniform diameter. 



A. Diameter of individual filaments 5 to 9 microns. 



1. Thioploca schmidlei. 



B. Diameter of individual filaments 2 to 5 microns. 



2. Thioploca ingrica. 



C. Diameter of individual filaments 1 to 2 microns. 



3. Thioploca minima. 



II. Filaments in common sheath of greatly different diameter. 



4. Thioploca mixta. 



1. Thioploca schmidlei Lauterborn. 

 (Ber. d. deut. bot. Ges., 25, 1907, 238.) 

 Named for Mr. Schmidlc. 



Individual filaments in a common 

 sheath 5 to 9 microns in diameter, clearlj- 

 segmented. Segments 5 to 8 microns in 

 length. Mucilaginous sheath 50 to 160 

 microns in diameter. Number of fila- 

 ments embedded in one sheath variable . 



Source : Various localities in Central 

 Europe . 



Habitat : So far reported only in fresh 

 water mud, containing hydrogen sulfide 

 and calcium carbonate. 



2. Thioploca ingrica Wislouch. (Ber. 

 d. deut. bot. Ges., 30, 1912, 470.) From 

 Ingria, an ancient district of Leningrad. 



Individual filaments in common sheath 

 2 to 4.5 microns in diameter, clearly seg- 

 mented. Segments 1.5 to 8 microns in 

 length. Mucilaginous sheath up to 80 

 microns in diameter. Number of fila- 

 ments in one sheath variable. 



Source : Various localities in Central 

 Europe. 



Habitat: Found in fresh water and 

 marine mud containing liydrogen sulfide. 



3. Thioploca minima Koppe. (Arch, 

 f. Hydrobiol., U, 1923, 630.) From 

 Latin minimus, least. 



Individual filaments in a common 

 sheath 0.8 to 1.5 microns in diameter. 



segmentation generally observable only 

 after removal of sulfur droplets. Seg- 

 ments 1 to 2 microns long. Mucilagin- 

 ous sheath up to 30 microns in diameter. 

 Number of filaments in one sheath 

 variable. 



Source : Various localities in Central 

 Europe. 



Habitat: Fresh water and marine 

 mud containing hydrogen sulfide. 



4. Thioploca mixta Koppe. (Arch. f. 

 Hydrobiol., I4, 1923, 630.) From Latin 

 mixtus, mixed. 



Individual filaments in a common 

 sheath of two clearly different sizes, 

 comprizing both filaments of 6 to 8 mi- 

 crons, and filaments of about 1 micron 

 in diameter. The former are clearly 

 segmented, with segments of 5 to 8 mi- 

 crons in length. In the latter segmenta- 

 tion is visible after removal of sulfur 

 droplets; segments 1 to 2 microns long. 

 Mucilaginous sheath usually about 50 

 microns thick. Number of filaments in 

 one sheath variable. 



Source: Reported so far onlj' from 

 Lake Constanza. 



Habitat : Fresh water mud containing 

 hydrogen sulfide. 



Appendix: In addition to the above 

 genera and species, a number of insuffi- 

 ciently characterized, filamentous sulfur 

 bacteria which may be related to the 



