Essays: Scientific, Political, & Speculative; Vol. 1 of 3 / Library Edition (1891), Containing Seven Essays not before Republished, and Various other Additions.

by Herbert Spencer

[50] A Treatise on Comparative Embryology, by F. M. Balfour, Vol. ii, chap. xiii.

[51] Sachs, p. 210.

[52] Ibid. pp. 83-4.

[53] Ibid. p. 185.

[54] Ibid. 80.

[55] Sachs, p. 83.

[56] Ibid. p. 147.

[57] A Treatise on Comparative Embryology. By Francis M. Balfour, LL.D., F.R.S. Vol. ii, p. 343 (second edition).

[58] Balfour, l.c. Vol. ii, 400-1.

[59] Balfour, l.c. Vol. ii, p. 401.