504 GENERAL SYSTEMATIC BACTERIOLOGY 



solidas, singulas vel plures simul cystidibus universalibus amplis, crassis homo- 

 genis, non lamellosis, gelatinoso-subcartilagineis, involutas, arete consociatis, 

 Cystides speciales nullae. Coccorum divisio alternatim in tres directiones. 



The genus is discussed by Migula (1900, p. 1042) (1904, p. 148) 

 E. F. Smith (1905, p. 163) and Frost (1911, p. 61). Smith gives the 

 following description: 



Families small, compact, enveloped singly or several together in a gelatinous 

 cyst, capable of swarming. When the families have reached a definite size they 

 escape from the gelatinous cyst, the latter either swelling and softening uniformly 

 or at some particular spot. The escaped cells either pass into the swarm stage or 

 unite into a larger fused complex of families, the individual cells of which sepa- 

 rate and swim away only after a long time, and by means of much vigorous 

 struggling. 



Orla-Jensen (1909, p. 334) incorrectly made this generic name a 

 synonjnn of Rhodocystis. 



Buchanan (1918, p. 466) include this as the first genus of the tribe 

 Thiocapseae with the following description. 



Usually 4 to 20 or 30 cells massed into small, compact families, enveloped 

 singly or several together in a gelatinous cyst, capable of swarming. When the 

 families have reached a definite size they escape from the gelatinous cyst, the lat- 

 ter either swelling and softening uniformly or at some particular spot. The 

 escaped cells either pass into the swarm stage or unit into a larger fused complex 

 of families. Cells are light colored, single cells almost colorless. In masses the 

 cells show a beautiful violet or red violet color. The cells are frequently quite 

 filled with sulphur granules. 



The type species is Thiocystis violacea Winogradsky. 



Bergey et al. (1923, p. 395) used the same description. 



Thioderma. A name proposed by Miyoshi (1897, p. 158) to include 

 certain sulphur bacteria. Two species were described, Thioderma 

 rubrum and Th. roseuni. The later is described as follows: Thioderma 

 roseum nov. gen. e spec. CeUs spheroidal, 2.5/i long and 1.5/z wide of 

 a light rose color, containing small, inconspicuous sulphur granules. 

 United into thin, removable, smooth purple red skin. On grass culms, 

 leaves, etc., on soil. Migula (1900, p. 1044) concluded the generic 

 name to be a synon3nii of Lamprocystis. 



Buchanan (1918, p. 468) included this as the second genus of the 

 tribe Thiopedieae with the following description: 



Cells spheroidal, light rose in color, containing small, inconspicuous, sulphur 

 granules. United into thin purplish membrane. 

 The type species is Thioderma roseum Miyoshi. 



