FAMILY BEGGIATOACEAE 993 



6. Beggiatoa minima Winogradsky. not a Beggiatoa.) From Latin mini- 



(Winogradsky, Beitr. z. Morph. u. mus, least. 



Physiol, d. Bacterien, I. Schwefelbac- Filaments less than 1 micron in diam- 



terien, 1888,25; Beggiatoa minor Uphoi, eter, of uniform width. Normally ap- 



Arch. f. Hydrobiol., 18, 1927, 79; not pears unsegmented; length of segments 



Beggiatoa minima Warming, Om Nogle about 1 micron. 



ved.DanmarksKysterlevende Bakterier, Habitat: Fresh water and marine en- 



1876, 52, which from the description is vironments containing hydrogen sulfide. 



Genus III. Thiospirillopsis Uphof. 



(Arch. f. Hydrobiol., 18, 1927, 81.) From Greek Iheion, sulfur M. J j. spirillum, 

 spirillum and Greek opsis, appearance. 



Filamentous, colorless sulfur bacteria, segmented, and spirally wound. Exhibit 

 creeping motility, combined with rotation, so that the filaments move forward with 

 a corkscrew-like motion. The tips produce oscillating movements. Resembles 

 Spindina among the Oscillatoriaceae . 



The type species is Thiospirillopsis floridana Uphof. 



1. Thiospirillopsis floridana Uphof. water at Wekiwa Springs and Palm 



(Arch. f. Hj'drobiol., 18, 1927, 83.) Springs, Florida. A very similar or- 



Named from Florida, the place where ganism has been observed at Pacific 



it was first found. Grove, California, in a marine aquarium 



Filaments 2 to 3 microns in diameter. where hydrogen sulfide had been gener- 



Segmentation difficult to observe with- ated by sulfate reduction. The genus 



out special precautions; segments about Thiospirillopsis may, therefore, be more 



3 to 5 microns long. The spiral windings wide-spread than is generally believed, 

 are regular. Habitat: Probably widely distributed 



Source: Found in the sulfur spring in water containing sulfur. 



Genus I V. Thioploca Lauterborn. 



(Ber. d. deut. botan. Ges., ^-5, 1907, 238.) Name derived from Greek theion, sulfur, 

 and ploka, braid. 



Filaments of Beggiaioa-Yike appearance, but occurring in parallel or braided 

 bundles, enclosed by a common wide slime-sheath. The latter is frequently incrusted 

 on the outside with detritus. Within the sheath the individual filaments are motile 

 in the manner of Beggiatoa; the filaments are segmented, the terminal segments often 

 tapering. 



Resembles closely the genera Hydrocoleus and Microcoleus among the Oscilla- 

 toriaceae . 



It is doubtful whether the members of the genus Thioploca are true colorless sulfur 

 bacteria; most investigators of these forms have reported a greenish-blue coloration 

 of the filaments. Only the regular occurrence of sulfur droplets in filaments taken 

 from their natural habitat stamps the organisms as sulfur bacteria. In view of the 

 close relationship of the Beggiatoaceae to the blue-green Oscillatoriaceae, this is, 

 however, a minor issue. 



Four species have been described to date. Three correspond, with respect to the 

 individual filaments, to Beggiatoa arachnoidea, Beggiatoa alba, and Beggiatoa lepto- 

 mitiformis respectively; the fourth appears to be a combination of the first and third 



