[AO]From the absence of interblending in some cases (to be considered shortly), both brown and green forms may be produced; and under certain circumstances, even a power of becoming either brown or green in the presence of appropriate stimuli.
[AP]Wallace, "Darwinism," p. 172, where other examples are cited.
[AQ]Ibid. pp. 217, et seq.
[AR]Journal of the Linnæan Society, vol. xix. No. 115: "Zoology."
[AS]"Animals and Plants under Domestication," p. 145.
[AT]Ibid. chap. xvii.
[AU]"Darwinism," p. 326.
[AV]"Animals and Plants under Domestication," vol. ii. p. 65. For Darwin's general conclusions on hybridism, see vol. ii. p. 162 of the same work.
[AW]"In every case there are two factors, namely, the nature of the organism and the nature of the conditions. The former seems to be much the more important; for nearly similar variations sometimes arise under, as far as we can judge dissimilar conditions; and, on the other hand, dissimilar variations arise under conditions which appear to be nearly uniform" ("Origin of Species," p. 6).
[AX]See "Evolution without Natural Selection," by Charles Dixon. This author's facts are valuable; his theories are ill digested.