[4] M. Bombarda, Comptes rendus Congrès Internationale de l'Anthropologie Criminelle, Amsterdam, p. 212.
[5] Lacassagne, "De la Criminalité chez les Animaux," Revue Scientifique, 1882.
[6] Steinach, "Utersuchungen zu vergleichende Physiologie," Archiv für die Gesammte Physiologie, Bd. lvi, 1894, p. 320.
[7] Féré, Comptes-rendus Société de Biologie, July 30, 1898. We may perhaps connect this with an observation of E. Selous (Zoölogist, May and Sept., 1901) on a bird, the Great Crested Grebe; after pairing, the male would crouch to the female, who played his part to him; the same thing is found among pigeons. Selous suggests that this is a relic of primitive hermaphroditism. But it may be remembered that in the male generally sexual intercourse tends to be more exhausting than in the female; this fact would favor a reversion of their respective parts.
[8] E. Selous, "Sexual Selection in Birds," Zoölogist, Feb., 1907, p. 65; ib., May, p. 169. Sexual aberrations generally are not uncommon among birds; see, e.g., A. Heim, "Sexuelle Verirrungen bei Vögeln in den Tropen," Sexual-Probleme, April, 1913.
[9] See Moll, Untersuchungen über die Libido Sexualis, 1898, Bd. i, pp. 369, 374-5. For a summary of facts concerning homosexuality in animals see F. Karsch, "Päderastie und Tribadie bei den Tieren auf Grund der Literatur," Jahrbuch für sexuelle Zwischenstufen, Bd. ii, 1899, pp. 126-154
[10] Muccioli, "Degenerazione e Criminalità nei Colombi," Archivio di Psichiatria, 1893, p. 40.
[11] L'Intermédiare des Biologistes, November 20, 1897.
[12] R. I. Pocock, Field, 25 Oct., 1913.
[13] R. S. Rutherford, "Crowing Hens," Poultry, January 26, 1896.