i3o SULPHUR BACTERIA 



use to designate a single member of the group of Bacteria. 

 The word Bacterie which often appears in German hterature 

 as the singular of Bacterien (or Bakterien) is not so suitable. 

 The following terms are used in this work :- — 



Thiobacilhis. Short rods, colourless, and with sulphur contents. 

 Rhodobacillns. ,, coloured, and no ,, ,, 



Rhodothiohacillus. ,, coloured, and with ,, ,, 



If the ciliation is polar instead of peritrich the term 

 Pseudomonas miust replace th.at of Bacillus, with the same 

 meaning as in Migula's classification. Thus there are theo- 

 retically six genera, four coloured and two colourless. In 

 this section only the genera Thiobacilhis and Thiopseudo- 

 monas are considered. Both Thiobacillus and Rhodobacilhis are 

 already in current use, with the same meaning as is given to 

 them in this work. The former word, however, is frequently 

 used loosely to indicate certain thionic acid bacteria, and in 

 particular Thiobacillus thiooxidans which in the strict sense 

 is not one of the sulphur bacteria. Up to the present the term 

 Thiobacillus has been used in the publications of American 

 writers as a convenient catalogue name, devoid of any phyletic 

 significance. 



Genus i. — Thiobacillus (Ellis).* 



Colourless, motile, or non-niotile, rod-shaped bacteria. 

 Cilia presumed peritrich. 



Thiobacillus Bovistus (Molisch), Ellis. 



Syn. Bacterium Bovisia (Molisch). 



Literature. — Molisch (5). 



Description. — A marine organism living a colonial life en- 

 closed in bladder-like slimy colonies measuring up to 4 mm. 

 in thickness. The outer surface of the bladder is made up of 



*It has been shown (Ellis (i)) that the mode of insertion of the ciha 

 in bacteria is a constant feature. An organism with peritrich cilia is always 

 peritrich, and in the same way an organism with polar ciliation is constant 

 to that mode of insertion. This is important for systematic purposes. 

 As the majority of the rod bacteria have peritrich cilia it is advisable to 

 assume that an organism of this class has peritrich cilia when the ciliation 

 is unknown and, pending further investigation, to place it in the genus 

 Thiobacillus. 



