Abstract: A diagram showing the life cycle of Porphyra tenera Kjellm. was published about a year ago in this journal[1]. Further studies have shown that the Conchocelis-phase liberates its conchosperes only between 15℃ and 20℃[2]. It follows that the summer and autumn forms of the dwarf porphyras which appear only in water temperature higher than 20℃ cannot arise from these spores; the two lines leading from the conchospores to these two forms of the dwarf porphyra must therefore be deleted. This and a few other minor points make it necessary to prepare a revised diagram which is herewith presented.