[3] This paragraph is taken from “Animal Life and Intelligence,” p. 28.
[4] The following paragraphs are taken with some slight changes from “Animal Life and Intelligence,” pp. 30–35.
[5] D. H. Scott, “An Introduction to Structural Botany,” part ii., “Flowerless Plants,” pp. 70, 71.
[6] Ibid., p. 71.
[7] Kerner, “Natural History of Plants,” translated by F. W. Oliver, vol. i., p. 145.
[8] Kerner, “Natural History of Plants,” vol. i., p. 536.
[9] Kerner, “Natural History of Plants,” vol. ii., p. 132.
[10] Darwin, “Fertilization of Orchids,” 2nd edit., pp. 191, 192.
[11] “Mental Evolution in Animals,” p. 50.
[12] Ibid., p. 51.