[53] Geoffrey Mortimer (W.M. Gallichan), Chapters on Human Love, pp. 17-18.
[54] Letourneau, Evolution of Marriage, p. 16.
[55] Letourneau, Evolution of Marriage, p. 12.
[56] Evolution of Sex, pp. 7-8.
[57] Epinas, Soc. Animales, p. 326; Darwin, Descent of Man, p. 433.
[58] Letourneau, Evolution of Marriage, p. 27.
[59] Ellis, Psychology of Sex, Vol. VI. p. 422.
[60] One of the most charming accounts of the loves of birds is given in a chapter on "Music and Dancing in Nature," in a volume entitled, The Naturalist in La Plata, by W.H. Hudson.
[61] Audubon, Scènes de la Nature, Vol. I. p. 350.
[62] Audubon, Scènes de la Nature, Vol. II. p. 50.