PLATE IX. 



Fig. 1 Spirogyra decimina. 



a, form; b, conjugating filaments. 

 " 2 Spirogyra quadrata. 



a. fruiting filament. 

 " 3 Spirogyra mirabilis. 



a, fruiting filament. 

 " 4 a Spirogyra insignis brauuii. 



4, conjugating filaments. 



