PLATE I. 



A. SARGASSUM, page 14. 



Fig. 1, a branch of S. vulgare; the natural size. 2, a 

 receptacle. 3, section of the same. 4, a spore. 5, a 

 vesicle, cut open ; all more or less magnified. 



B. CYSTOSEIRA, page 16. 



Fig. 1, a branch of C. fibrosa ; the natural size. 2, a 

 receptacle and vesicle. 3, section of the receptacle. 

 4, a spore ; all magnified. 



C. HALIDRYS, page 15. 



Fig. 1, part of a branch of H. siliquosa; the natural 

 size. 2, a vesicle, cut open, showing the internal 

 septa, connected by slender threads. 3, part section 

 of a receptacle. 4, spore ; all magnified. 



D. Fucus, page 18. 



Fig. 1, part of a frond of F. vesiculosus ; the natural 

 size. 2, part section of a receptacle, showing three 

 conceptacles. 3, a spore, containing eight sporules ; 

 both magnified. 



