PLATE VI. 



PIG. PAGE 



1. Laminaria Phyllitis 5i 



1 a, slice of frond, magnified. 



2. Lomentaria ovalis 125 



2 a, a branchlet with spore-conceptacles, mag- 



nified. 



2 b, a branchlet with tetraspores, magnified. 



3. Porphyra vulgaris 248 



3 a, vertical section of frond, magnified. 



