114 SULPHUR BACTERIA 



each constriction being ring-shaped and transverse. The 

 threads are septate, and their ends often pointed. 



Wislouch states that the members of this genus are 

 shghtly blue in colour, due to the presence of phycocyan and 

 chlorophyll. It is probably physiologically intermediate 

 between the Cyanophycece and the Leuco-thiohacteria, but 

 it is included in this group for the sake of completeness. 



Thioploca Schmidlei (Lauterborn), 1907. 



Literature. — Lauterborn (5), 1907 ; Koppe, 1923. 



Description. — Each "rope" may extend to 3 — 4 centi- 

 metres, and may itself be one of a number of strands forming 

 a thicker rope. The thickness of such a " rope " is 50 — 60)u-, 

 and within it the closely adpressed threads at its centre exhibit 

 gentle gliding movements passing over one another, but they do 

 not leave the " rope " in their movements. Also there appears 

 to be some directive force in the community as a whole, for 

 the movements of two neighbourhood threads are always in 

 opposite directions. Sculpturing effects are produced on the 

 surface of the " ropes " owing to the incrustation of mineral 

 matter from the surrounding water. At certain periods, or 

 under certain conditions, the slime opens out and from it 

 emerge threads, which swim away and doubtless form the 

 nucleus of new colonies, although their development has not 

 been investigated. Reproduction is by fission. Lauterborn 

 also observed the intertwining, after separation, of the two 

 sections of a dividing thread. 



The threads are septate, the length of each segment being 

 i-| times its breadth. The threads in a young colony, accord- 

 ing to Lauterborn's figures, do not show septation. The 

 sulphur granules are so numerous and small that the threads 

 appear black under the microscope. 



Habitat. — Found in calcareous mud below 15 — 20 metres 

 depth either in marine, or brackish, or fresh water. Recorded 

 from Ermatingen ; from the neighbourhood of Solingen, in 

 a bay of the Rhine ; from near Strassburg; from the Neva; 

 and from the neighbourhood of Konigsberg. 



