Several interesting studies have been made in the past on the nitrogen metabolism in seaweeds. Haas and Hi11 (1931) and Haas, Hill and Karstens (1935) isolated water-soluble peptides from the brown alga Pelvetia canaliculata and explained their presence as due to lack of metabolic balance traceable to either desiccation or low illumination. To obtain further evidence Haas, Hill and Russel-Wells (1938) examined the calcareous algae Corallina squamata Ellis, Lithophylum incrustans Foslie, Amphiora capensis Aresch and Galaxaura subverticillata Kjell. A number of unencrusted algae were also examined, but so far among the latter group peptides were found only in the two species, Pelvetia canaliculata and Griffithsia flocculoses. It was found that the encrusted forms contained crude peptides to the extent of 0.05 to 0.29% of the dry weight.