RHODO-THIOBA CTERIA 



169 



Each cell is globular but capable of altering its shape. 

 Dimensions 2-8 — 3-4/^ in diameter. The cell elongates before 

 division to approximately 6/x. Colour a delicate rose (Fig. 45). 



Habitat. — Found in waters containing sulphuretted hydro- 



FiG. 45. — Amoebohacter roseus. {a) Encysted condition, [b) Emergence 

 of cells from cyst and formation of swarm cells, x 1500. 



gen in solution. Skene obtained this organism from material 

 supplied from Kiel, and found that he could obtain impure 

 cultures by adding to the material sulphuretted hydrogen, 

 ammonia (as a source of nitrogen), and chalk (as a neutralizing 

 agent). 



Amcebobacter bacillosus (Winogradsky). 



Literature. — Winogradsky (2), 1888 ; Lauterborn (7), 191 5. 

 Cells rod-shaped, 2 — 4/x long and 17/i, thick. Colour red. 

 Habitat. — In waters containing sulphuretted hydrogen in 

 solution. 



Am(Ebobacter granula (Winogradsky). 



Literature. — Winogradsky (2), 1888. 



Cells very small, about 0-5/x in diameter, and almost 

 colourless. Each contains a single sulphur globule so highly 

 refractive that it blurs the contour of the coccus. 



Habitat. — In waters containing sulphuretted hydrogen in 

 solution. 



Genus 2.- — Thiodictyon (Winogradsky). 

 Literature. — Lankester (i), 1873, and (2), 1876; Winogradsky 

 (2), 1888; Migula (3), 1900 ; Kolkwitz (3), 1909 ; 

 Bergey, 1923 ; Bavendamm, 1924. 



Description. — An organism was sketched by Lankester in 

 1873 as a pleomorphic phase of Bacterimn riibescens which 



