[46] Vide Schultze, Archiv. f. mikr. Anat. Vol. XI.; and F. M. Balfour, Monograph on the Development of Elasmobranch Fishes.
[47] Vide Klein, Quart. Journal of Micr. Science, April, 1876. Bambeke, Mem. Cour. Acad. Belgique, 1875. His, Zeit. für Anat. u. Entwicklung. Vol. I.
[48] Vide Bambeke, loc. cit.
[49] Vide Bobretzky, Zeitschrift für wiss. Zoologie, Vol. XXIV., 1874.
[50] Loc. cit.
[51] Bulletins de l’Acad. Belgique, Tom. XXIX., 1870.
[52] Though less obvious in the ovum of the fowl than in that of some other types, they may nevertheless be demonstrated there without very much difficulty.
[53] Quart. Journ. of Micr. Science, Vol. XV. pp. 39, 40.
[54] Quart. Journ. of Micr. Science, Vol. XVIII. p. 41.
[55] At the time when my observations on Elasmobranchii were carried out, this peculiar condition of the nucleus had not been elucidated.