1. Birnsteil, M. L., Ann. Rev. Plant Physiol., 18, 25 (1967).
2. Perry, R. P., in Lima-de-Faria, A. (ed.), Handbook of Molecular Cytology, North-Holland Publishing Co., Amsterdam (1969), p. 620.
3. Wu, R., and Warner, J., personal communication.
4. Maisel, J.C., and McConkey, E.H., J. Mol. Biol., 61, 251 (1971).
5. Craig, N.C., and Perry, R.P., Nature New Biol., 229, 75 (1971).