1. Kurogi, M., Bull. Tohoku Reg. Fish. Res. Lab. 15, 33 (1959).
2. Dring, M. J., J. Marine Biol. Assoc. UK, 47 (in the press, 1967).
3. Wilson, J. R., and Schwabe, W. W., J. Exp. Bot., 15, 368 (1964).
4. Hendricks, S. B., and Borthwick, H. A., in Chemistry and Biochemistry of Plant Pigment (edit. by Goodwin, T.W.), 405 (Academic Press, London, 1965).
5. Bauer, L., and Mohr, H., Planta, 54, 68 (1959).