In Descent 1: 270 n. 9, CD referred to Edmund Saul Dixon’s comment in Ornamental and domestic poultry (E. S. Dixon 1848) that the eggs of the guinea fowl are infertile when more than one female is kept with the male. The reference was removed in Descent 2d ed., p. 220. This first part of the letter is on a separate scrap of paper pasted to the second part.