54 Synopsis of the Bacteria and Yeast Fungi. 



older parts, colourless in the younger, many times branched, 

 very slimy. During spore-formation, partly- milk-white, 

 partly red-coloured. Cells 49 /* long, 3 ju, thick. (Fig. 56.) 

 In stagnant and flowing water. 



The flakes consist of an enormous mass of long, variously combined 

 threads, which are formed of rows of cells, surrounded by a slimy, 



Fig. ^.-Spharotilus natans (after Kutzing). 



evanescent sheath. These threads often assume a shrubby branched 

 form, and are attached to water-plants, or float in a thin layer on the 

 water. In the formation of spores, the protoplasm of the cells breaks 

 up into numerous minute, strongly refringent portions, which become 

 round spores, red at maturity, afterwards of a brown colour. These 

 are set free by the dissolution of the mother-cell. They germinate very 

 quickly, and grow into threads which are either isolated, or united with 

 the parent-threads or with other threads as well. These daughter- 

 threads, proceeding from the germinating spore, are at first undivided ; 

 not till after a time do they break up into the typical rows of cells. 

 Sometimes the growth of the spores into threads takes place while they 

 are still within the mother-cell. 



Spharotilus ochraceus, de Brebiss in litt., Kutzing, " Species Alga- 

 rum," p. 147, does not belong to this genus. 



XVI. CRENOTHRIX, Cohn. 



Threads cylindrical, somewhat clavately thickened up- 

 wards, articulated, provided with a sheath. Multiplication 

 by means of the joints, which escape from the sheath and 

 grow into threads. Reproduction by spores, which are 

 formed in the sheath by further subdivision of the joint-cells. 

 The spores either grow directly into threads, or form by 

 continued subdivision gelatinous colonies of roundish cells, 

 which afterwards produce threads. 



