FAMILY I. THIORHODACEAE 41 



Genus III. Thiocapsa Winogradsky, 1888. 



(Schwefelbacterien, Leipzig, 1888, 84.) 



Thi.o.ca'psa. Gr.n. ihiiun sulfur; L.n. capsa a box; M.L. fem.n. Thiocapsa sulfur box. 



Cells spherical, occurring in families of irregularly arranged individuals held together 

 in a common slime capsule. The aggregates are spread out flat on the substrate. Motility 

 not observed. As the colony grows, the capsule bursts, and the cells are spread apart. Gen- 

 eral morphology and development thus appear similar to that in the genus Aphanocapsa 

 among the blue-green algae. Contain bacteriochlorophyll and carotenoid pigments; capable 

 of photosynthesis in the presence of hydrogen sulfide. Under such conditions sulfur is stored 

 in the form of globules in the cells. This genus is so much like TMothece that it is doubtful 

 whether a distinction can be maintained. 



The type species is Thiocapsa roseopersicina Winogradskj'. 



Key to the species of genus Thiocapsa. 



I. Individual cells about 3 microns in diameter. 



1. Thiocapsa roseopersicina. 

 II. Individual cells about 1.5 microns in diameter. 



2. Thiocapsa floridana. 



1. Thiocapsa roseopersicina Winograd- Illustration: Winogradsky, loc. cit., Plate 



sky, 1888. (Schwefelbacterien, Leipzig, 1888, IV, fig. 15. 



• •/ T J- 2. Thiocapsa floridana Uphof, 1927. 



ro.se.o.per.si.ci na. L. adj. roseus rosy; tt i u- i ^ 



Gr. noun persicus the peach, Persian apple, 

 Persian; M.L. adj. roseopersicinus rosy- 



(Arch. f. Hydrobiol., 18, 1927, 84.) 



flo.ri.da'na. M.L. adj . floridanus pertain- 

 ng to Florida. 



^^^.. , ■ 1 r. r o • • 1- Cells spherical, about 1.5 microns in di- 



Cells spherical, 2.5 to 3 microns in diam- 



ameter. In groups of irregular colonies, each 



eter, occurring in families of irregularly ,,,j.rounded by a common capsule, several 



arranged individuals held together in a colonies being stuck together. Motility not 



common slime capsule. Motility not ob- observed 



served. Usually a distinct rose-red. Stored Source: Palm Springs, Florida and Lake 

 sulfur droplets may attain a considerable Sakskoje, near Eupatoria, Crimea, 

 size. Habitat: Mud and stagnant water con- 

 Habitat: Mud and stagnant bodies of taining hydrogen sulfide and exposed to 

 water containing hydrogen sulfide and ex- light; sulfur springs. Probably ubiquitous, 

 posed to light; sulfur springs. Illustration: Uphof, ibid., 83, fig. VI. 



Genus IV. Thiodictyon Winogradsky, 1888. 



(Winogradsky, Schwefelbacterien, Leipzig, 1888, 80; Rhododictyon Orla-Jensen, Cent. f. 

 Bakt., II Abt., 22, 1909, 334.) 



Thi.o.dic'ty.on. Gr. noun thium sulfur; Gr. noun dictyum or dictyoii net; M.L. neut.n. 

 Thiodictyon sulfur net. 



Cells rod-shaped, frequently with pointed ends, somewhat resembling spindles. Form 

 aggregates in which the cells become arranged end to end in a net-like structure, somewhat 

 reminiscent of the shape of the green alga Hydrodictyon. The shape is not constant; cells 

 may also form more compact masses. Sometimes groups of cells separate from the main 

 aggregate by active movements. Common gelatinous capsule not observed. Contain bac- 

 teriochlorophyll and carotenoid pigments; cells usually very faintly colored. Capable of 

 photosynthesis in the presence of hydrogen sulfide, the cells then storing sulfur as small 

 globules. 



