384 THE MICROSCOPIST. 



C.floccosa. More robust, articulations once or twice 

 longer than broad. 



C. cerea. Yellow-green tufted filaments, thick as hog's 

 bristles. 



C. melagonium. Erect tufted filaments. 



C. linum. Long, tangled filaments. 



4. Ulothrix (?). Filaments simple, often fasciculated, 

 joints short. Zoospores four ciliated ; two, four, or more 

 in a cell. Fresh water. 



5. Stigeodonium (?). Filaments branched, ramules run- 

 ning out into slender points, cell-walls often dissolving to 

 emit zoospores. Zoospores four ciliated, one in a cell. 



5. ZYGNEMACE.E. Fresh-water filaments, no evident 

 gelatin, of a series of cylindric cells, straight or curved. 

 Cell-contents often arranged in elegant patterns on the 

 walls. Reproduction from conjugation followed by a true 

 spore, in some genera dividing into four sporules. 



1. Zygnema. Filaments simple, green contents ar- 

 ranged in two globular or stellate masses in each cell. 

 Conjugate by transverse processes. Spores in a parent 

 cell on cross branch. 



* Spores in one of parent cells. 

 Z. cruciata. Spores globose. 



Z. stagnalis. 

 Z. insignis. 

 Z. bicornis. 



* * Spores in cross branches. 

 Z. immersa. 



Z. conspicaa. 

 Z. decussata. 

 Z. RalfsiL 

 Z. pectinata. 



2. Spirogyra. Filaments simple, green contents in one 

 or more spiral bands on cell-wall. Conjugate by trans- 



