1. Yamane, J., and Egashira, T., Zool. Mag., Tokyo, 36, No. 340 (1924). Hammond, J., and Walton, A., J. Genet., 20, 401 (1929).
2. Chang, M. C., and McDonough, J. J., J. Hered., 46, 41 (1955).
3. Adams, C. E., paper submitted to J. Endocrin. (in the press).
4. Adams, C. E., J. Endocrin., 13, 296 (1956).
5. Venge, O., Ann. Roy. Agric. Coll., Sweden, 21, 417 (1954).