[2018] Mygge, loc. cit. p. 171.

[2019] Darwin, ‘Cross and Self Fertilisation,’ pp. 439, 458.

[2020] Ibid., p. 439. G. H.  Darwin, in ‘Jour. Statist. Soc.,’ vol. xxxviii. p. 175.

[2021] Quoted by Düsing, loc. cit. p. 249.

[2022] Mitchell, in ‘Mem. Anthr. Soc.,’ vol. ii. p. 447.

[2023] Cf. Devay, ‘Du danger des mariages consanguins,’ p. 10.

[2024] G. H.  Darwin, in ‘Jour. Statist. Soc.,’ vol. xxxviii. p. 163.

[2025] Ibid., pp. 175, et seq.

[2026] v. Martius, loc. cit. vol. i. p.  334.

[2027] Bates, loc. cit. vol. ii. pp. 199, et seq.