[36] Cf. especially in this connexion Häcker’s paper Über die Schicksale der elterlichen und grosselterlichen Kernanteile (1902).
[37] Each nucleus contains a duplicate set of chromosomes, the one of maternal, the other of paternal origin, and either of these sets alone suffices for development. This is clearly shown by the experiments of Loeb (1899) and Wilson (1901) on the artificial parthenogenesis of the sea-urchin egg; and those of O. Hertwig (1889 and 1895), Delage (1899) and Winkler (1901), on the fertilization of enucleated Echinoderm eggs (Merogony, Delage). The fact that in some forms, e.g. Ascaris megalocephala var. univalens, only one chromosome is derived from each parent, originally led Boveri to conclude that all chromosomes must necessarily be physiologically equivalent.
[38] Über mehrpolige Mitosen als Mittel zur Analyse des Zellkerns (1902).
[39] Über das Auseinandergehen von Furchungs- und Gewebezellen in kalkfreien Medium (1900).
[40] “Entwicklungsmechanische Studien V.” (Zeit. für wiss. Zool., Bd. lv., 1892).
[41] See Geddes and Thomson, Sex, esp. pp. 127, 137 and 139.
[42] The equivalence of the germ nuclei in development is shown by the experiments on the fertilization of enucleated eggs and artificial parthenogenesis already referred to.
[43] O. Hertwig, 1873; but esp. van Beneden, 1883.
[44] Häcker, “Über die Selbstständigkeit der väterlichen und mütterlichen Kernbestandteile,” Arch. f. mikr. Anat. Bd. xlvi. (1896).
[45] First discovered by van Beneden (1883, 1887) for the egg of Ascaris.