CHAPTER IX. 



RHODO-THIOBACTERIA (COLOURED SULPHUR 

 BACTERIA). 



Family 3. RhodothiospirillacecB. Genus i. Riiodothiospivillum. 



Family 4. RhodocapsacecB. Genus i. Rhodocapsa ; Genus 2. Rhodothece ; 



Genus 3. Rhodothiosarcina. 

 Family 5. ThiocapsacecB. Genus i. Thiocapsa ; Genus 2. Thiocystis ; Genus 



3. ThiosphcBrion. 

 Family 6. AmcebobacteriacecB. Genus i. Amcebobacter ; Genus 2. Thio- 



dictyon. 

 Family 7. Thiopediacece. Genus i. Thiopedia. 



Family 3. — Rhodothiospirillace.e. - 

 Spirally wound, motile, coloured organisms. Ciliation 

 polar. 



Genus i.—Rhodothiospirillum (Ellis). 



Literature. — Ehrenberg (2), 1838 ; Cohn (7), 1872 ; Wino- 



gradsky (2), 1888; Butschli (i), 1890 ; Zettnow (2), 



1897; Migula (3), 1900 ; Buder (2), 1915; Metzner, 



1920. 



Winogradsky's term Thiospirillum was designed to include 



all spirilla with sulphur contents. The occurrence of these 



organisms in sulphur waters has been known for nearly a 



hundred years. Early descriptions of spiral sulphur bacteria 



37. — Ophidonionas sanguinea. 



are incomplete since no distinction was made between fat 

 globules, volutin, and sulphur globules. 



In Winogradsky's genus, both coloured and uncoloured 

 spirilla were included, so that a change of nomenclature is 



160 



