FAMILY THIORHODACEAE 



859 



terien, Leipzig, 1888, 100; Bacillus 

 tninutissimus Trevisan, I generi e le 

 specie delle Batteriacee, 1889, 18; Bac- 

 terium minutissimum DeToni and Trevi- 

 san, in Saccardo, Sylloge Fungorum, 8, 

 1889, 1028.) From Latin minutus and 

 diminutive, very minute. 



Cells: About 1 to 1.2 micron by 2 mi- 

 crons. Also from 0.5 to 0.7 micron by 

 0.6 to 1 micron (Issatclienko, Recherches 

 sur les microbes de I'oc^an glacial arc- 

 tique, Petrograd, 1914, 253); and 1 to 3 

 microns by 2 to 5 microns (Issatclienko, 

 Borodin Jubilee Volume, 1929?, 9). 



Illustrations: Winogradsky, loc. cit., 

 PI. IV, fig. 8; Miyoshi, Jour. ColL Sci., 



Imp. Univ., Tokyo, Japan, 10, 1897, PL 

 XIV, fig. 18. 



Appendix : The measurements for Thio- 

 spirillum coccineum Hama (Jour. Sci. 

 Hiroshima Univ., Ser. B, Div. 2, Bot., 1, 

 1933, 158) which, according to descrip- 

 tion and figures {ibid., PI. 18, fig. 2; PL 

 19, fig. 2), is an unquestionable species 

 of Chromatium, are given as 2 by 4 to 

 15 microns. It thus closely resembles 

 the bacteria of the Chromatium minus, 

 C. vinosum, C. violaceum, and C mo- 

 lischii group. 



Chromatium sphaeroides Hama, loc. cit. 



Thiospirillum violaceum (Warming) 

 Winogradsky is probably also a member 

 of this assemblage. 



APPENDIX TO FAMILY THIORHODACAE. 



Three genera of sulfur purple bacteria have been proposed whose place and 

 nature are at present very doubtful. They follow here: 



a. Thiosphaerion Miyoshi, with the 

 single species Thiosphaerion violaceum 

 Miyoshi (Jour. Coll. Sci., Imp. Univ., 

 Tokyo, Japan, 10, 1879, 170). Occurs in 

 round colonies in which numerous bac- 

 teria are held together by mucus, though 

 not in a clearly discernible common cap- 

 sule. Individual cells ovoid, about 1.5 

 to 2 by 2.5 microns; motile. Resembles 

 Lamprocystis roseopersicina in many 

 respects. Reported once from Yumoto 

 Hot Springs, near X^ikko, Japan. 



Illustrations: Miyoshi, loc. cit., PL 

 XIV, fig. 24 a-b. 



b. Pelocliromatium Lauterborn, with 

 the single species Pelochromatium roseum 

 Lauterborn (Verhandl. naturhist. medi- 

 zin. Vereins, Heidelberg, X'.F. 13, 1915, 

 424). Forms small colonies in which 

 the bacteria are regularly arranged in 

 about 5 rows, from 2 to 4 cells high, 

 around a colorless central bod3^ The 

 entire colony actively motile and be- 

 haves like a single unit. Individual 

 cells bean- or vibrio-shaped, about 1 mi- 

 cron or less by 2 microns; the barrel - 

 shaped colony measures 2.5 to 4 by 4 to 8 



microns. The structure may represent 

 a complex of a colorless central bac- 

 terium surrounded by purple bacteria, 

 analogous to Chlorochromatium aggre- 

 gatum Lauterborn. Whether such struc- 

 tures have generic or even specific taxo- 

 nomic significance remains to be 

 determined. The lack of information con- 

 cerning the occurrence of sulfur globules 

 in the cells makes it doubtful whether 

 the organisms are sulfur purple bacteria 

 at all. Found twice by Lauterborn in 

 mud samples. 



Illustrations: Lauterborn, ioc. cit.,F\. 

 Ill, fig. 28, a-c. 



Utermohl suggested the name Lauter- 

 horniola minima Utermohl (Biol. Zen- 

 tralbl., 43, 1924, 605) for the small brown- 

 ish bacteria which form the covering of 

 the central body of Pelochromatium 

 roseum; according to this author the cen- 

 tral body is a larger bacterium, 1.5 by 7 

 microns which he named Endosoma 

 palleum. 



c. Thioporphyra Ellis, with the single 

 species Thioporphyra volulams Ellis 

 (Jour. Roy. Technic. Coll. Glasgow, 



