BACTERIA. 91 



2. Family Rhodobacteriacece. 



Contents of the cell coloured pink, red, or violet by bacterio-purpurin ; cell 

 containing granules of sulphur. 



( 1 ) Sub-family Thiocapsacece. 



Cells grouped in families ; division in two or three planes. 



(1) Genus Thiocystis, Winogradsky. Small families closely packed, surrounded 

 by one or more gelatinous cysts ; motile at all stages of existence. 



(2) Genus Thiocapsa, Winogradsky. Flat spreading colonies on substratum, 

 consisting of spherical cells loosely embedded in one mass of jelly ; motionless. 



(3) Genus Thiosarcina, Winogradsky. Family grouped in a packet form, 

 incapable of movement. Corresponding with genus Sarcina in the Eubacteria. 



(2) Sub-family Lamprocystaceoe. 



Cells combined in families. Division of cells first in three, and afterwards 

 in two, planes. 



(1) Genus Lamprocystis, Schroter. Families at first solid, then forming 

 hollow spherical mesh, and finally separating into small motile groups. 



(3) Sub-family Thiopediacece. 

 Cells grouped in families. Division in two planes. 



(1) Genus Thiopedia, Winogradsky. Families forming plates consisting of 

 motile cells arranged rectangularly. 



(4) Sub-family Amcebobacteracece. 

 Cells grouped in families ; division in one plane. 



(1) Genus Amcebobacter, Winogradsky. Cells grouped in families; division 

 in one plane. Families moving like Amoeba. Cells wrapped in threads of plasma. 



(2) Genus Thiotece, Winogradsky. Family with thick gelatinous cyst. Cells 

 loosely enclosed in a common jelly ; always motile. 



(3) Genus Thiodictyon, Winogradsky. Families consisting of small rods, 

 the ends of which are bound together to form a mesh. 



(4) Genus TJiiopolycoccus, Winogradsky. Families solid, motionless, con- 

 sisting of small densely packed cells. 



(5) Sub-family Chromatiacece. 

 Cells free and motile in some stages. 



(1) Genus Chromatium, Perty. Cells ellipto-cylindrical or elliptical, com- 

 paratively thick. 



(2) Genus Rhabdochromatium, Winogradsky. Cells free, spear or spindle- 

 shaped. Motile at certain stages, with polar cilia. 



(3) Genus Thiospirillum. Cells free, motile, spiral-shaped. Always motile. 



This system provides a survey of the great groups of 

 bacteria, classed together according to their form, structure, 

 and the course of their development. 



