PLATE XV. 



FIG. PAGE 



1. Striaria attenuata 62 



1 #, part of a branch, with spores, 



2. Cladophora laetevirens 261 



2 a, part of a branch, magnified. 



3. Cladophora lanosa 269 



3 a, part of a branch, magnified. 



4. Chaetomorpha Melagonium 273 



4 a, cells of thread, magnified. 



