The glycogen and glucose contents of salmon eggs, detached embryos, yolk sacs, and livers have been estimated periodically from fertilization to the end of yolk absorption. Glycogen is absent at the beginning, appears midway between fertilization and hatching, and later increases steadily in concentration, reaching a maximum of 0.53 mg. per 130 mg. egg. Glycogen storage by the liver begins suddenly some time after hatching, before which the muscles serve as a storage place. No glycogen ever appears in the yolk. The initial quantity of glucose is 0.064 mg. per egg. The concentration increases with development, is interrupted at hatching, and then continues to rise, reaching a maximum value of 0.29 mg. per egg. The glucose is distributed throughout all parts of the system, and its fluctuations parallel those of the water content, leading to the suggestion that the glucose concentration per unit of water is constant throughout development.