274 THE IRON HACTKKIA 



first described by Kiitzing. A second sheath-forming thread bacterium, allied 

 to the genus Cladothrix, was also examined by him, and named Sphaarot&ut natnii*. 

 It is still too imperfectly known to be dilated upon here, although ED. EIDAM (II.) 



FIG. 66. Crcnotlirix ]>'>ly."p<>ni. 



(irriniiiation of the cocci (//, within the sheath of tin- parent 

 thread. MHUH. about 600. ( . (// r Zpf.) 



also occupied himself with it. Associated with this colourless species is a second 

 (coloured) species, discovered by W. ZOPF (VIII.) in a Silesian river receiving 

 the drainage from a sugar-works. The 'cells of this, Sphu-rotil'i* roseus, contain 

 a yellow and a red colouring-matter, which circumstance is of itself sufficient to 

 distinguish it from all other [(colourless) species of thread bacteria hitherto 

 mentioned. 



