Another remarkable observation relating to the crosses of _muricata_ and _biennis_ has been published by Goldschmidt.[10] He finds that in the formation of this cross the female pronucleus takes no part in the development of the zygotic cell, but that when the male pronucleus enters, the female pronucleus is pushed aside and degenerates. As de Vries observed, the reciprocal hybrids are in each case very like the father ("_stark patroklin_"), a consequence which finds a natural explanation in the phenomenon witnessed by Goldschmidt. The results of the subsequent matings can also be readily interpreted on the same lines. Indications of maternal characters are nevertheless mentioned by de Vries, and if Goldschmidt's account of the cytology is confirmed, these must presumably be referred to the influence of the maternal cytoplasm. Clearly this new work opens up lines of exceptional interest. The interpretation I have offered above must probably be reconsidered. The distinction between the male and female cells of the types may no doubt be ultimately factorial, but it is difficult to regard such a distinction as created by a differential distribution of the ordinary factors. FOOTNOTES: [1] See Lotsy and Baur, Rep. Genetics Conf., Paris, 1911, pp. 416-426. Compare Lecoq on _Mirabilis jalapa_ × _longiflora_, Fécondation des Végétaux, 1862, p. 311. [2] _Rep. Evol. Ctee. R. S._, IV, 1908, p. 38. [3] _Ber. Deut. Bot. Ges._, 1908, XXVI, _a_, p. 672. [4] _Jour. Genetics_, 1, 1910, p. 57. [5] In Rep. 1 to Evol. Committee, 1902, p. 132, attention was called to this possibility, though of course at that date it was in sexual animals alone that it was supposed to exist. It had not occurred to me that even a hermaphrodite plant might be in this condition. [6] From the description of the offspring of _muricata_ used as mother. [7] de Vries, _Species and Varieties_, 1905, p. 259. [8] Zeijlstra in a recent paper announces that many _nanella_ plants are the subject of a bacterial disease to which he attributes their dwarfness. I gather that this does not apply to all _nanella_ plants and that some are dwarfs apart from disease. The matter may no doubt be further complicated from this cause. [9] _Zts. f. Abstamm._, 1912, VIII. [10] _Arch. f. Zellforschung_, 1912, IX, p. 331. CHAPTER VI VARIATION AND LOCALITY