PLATE 31 

 Ulva angusta S. and G. 

 Fig. 1. A microphotograph of a part of the surface. X 442. 



Monostroma areolatum S. and G. 



Fig. 2. A microphotograph of a part of the surface. X 442. 



The photographic work was all done by W. C. Matthews except plate 30, 

 which was done by E. W. Merrill. All the figures of plate 21, all but figure 5 

 of jilate 22 and figures 2, 3, 6, 7, and 8 of plate 24 were drawn by Dr. Helen M. 

 Gilkej'. All of plate 23 and figures 1, 4, and 5 of plate 24 were drawn by Miss 

 Almeda H. Nordyke. 



[324] 



