PLATE 21 



Ulva dactylifera S. and G. 



Fig. 1. Photograph of a whole plant, with the exception of a portion of the 

 base, the type. X 0.75. 



Ulva stenophylla S. and G. 



Fig. 2. A micro-photograph of a portion of the surface, showing the rounded 

 angles and relatively thick walls of the cells. X 442. 



[350] 



