546 



DESCRIPTION OF SPECIES. 



coloration, caused by impreg- 

 nation with oxide of iron. The 

 threads are distinctly articulated, 

 and ensheathed. The segments are 



set free when the sheath bursts, 

 and develop into new threads. In 

 other cases the segments remain 

 enclosed, and subdivide into discs, 



FIG. 218. CRENOTHRIX KUHNIANA. 



a, 6, c, d, e. Cocci in various stages of fission, x 600. 



/. Zoogloea of cocci, x 600. 



rj. Various forms of zoogleea, natural size. 



h. Colony of threads composed of rods grown out of a zoogloea of cocci. 



i r. Thread-forms ; some straight, others spiral, with more or less differentia- 

 tion between base and apex, (r) is composed of short rods at the base, and above 

 these of cylindrical segments, and at the apex these segments have divided into 

 cocci, x 600 (Zopf). 



