EXPLANATION OF PLATES. 
All figures are photographs after dried specimens, about "I; nat. size. 
Plate I. 
Porphyra umbilicalis (L.) J. Ag. 
1. Monoecious specimen showing a longitudinal limiting line between the male and the female 
part of the frond. (Helsingor, September). 
Small male specimen (f. laciniata); the marginal zone has produced antheridia. (Helsingør, 
September). 
m 
3. Female plant. The fertile zone above shows irregtlarly ramified spots caused by earlier 
maturation of the cystocarps here than in the surrounding parts. (Norre Sundby, Lim- 
fjorden, September). 
Plate II. 
1—3. Porphyra umbilicalis (L.) J. Ag. f. linearis (Grev.). 1, monoecious, 2, female, 3, male specimen 
(Frederikshavn, December—January). 
4—13. Porphyra leucosticta Thur. 
4—7. Sexual plants, (harbour of Skagen, April 1905, M. L. Mortensen). 
8. Asexual plant, possibly producing gonidia, (harbour of Skagen, July 1907). 
9—13. Small specimens being the under part of specimens which have exhausted their sper- 
matia and carpospores, (harbour of Skagen, July 1905). 
