[22] See "Natural Selection," pp. 60-75.

[23] "Principles of Biology," vol. i. p. 122.

[24] See "Natural Selection," chap. iii. p. 45.

[25] Loc. cit. p. 80.

[26] Ibid. p. 59.

[27] Loc. cit. p. 64.

[28] "Origin of Species," 5th edit. p. 104.

[29] "Animals and Plants under Domestication," vol. ii. p. 351.

[30] Loc. cit. pp. 109, 110.

[31] Heredity is the term used to denote the tendency which there is in offspring to reproduce parental features.

[32] Loc. cit. p. 64.

[33] Loc. cit. p. 60.

[34] The term "Vertebrata" denotes that large group of animals which are characterized by the possession of a spinal column, commonly known as the "backbone." Such animals are ourselves, together with all beasts, birds, reptiles, frogs, toads, and efts, and also fishes.

[35] It is hardly necessary to observe that these "sea-snakes" have no relation to the often-talked-of "sea-serpent." They are small, venomous reptiles, which abound in the Indian seas.

[36] "Origin of Species," 5th edit., 1869, p. 179.

[37] "Origin of Species," 5th edit., p. 532.

[38] Mr. A. D. Bartlett, of the Zoological Society, informs me that at these periods female apes admit with perfect readiness the access of any males of different species. To be sure this is in confinement; but the fact is, I think, quite conclusive against any such s.e.xual selection in a state of nature as would account for the local coloration referred to.

[39] Mr. Darwin, in the last (fifth) edition of "Natural Selection," 1869, p. 102, admits that all s.e.xual differences are not to be attributed to the agency of s.e.xual selection, mentioning the wattle of carrier pigeons, tuft of turkey-c.o.c.k, &c. These characters, however, seem less inexplicable by s.e.xual selection than those given in the text.

[40] I am again indebted to the kindness of Mr. A. D. Bartlett, amongst others. That gentleman informs me that, so far from any mental emotion being produced in rabbits by the presence and movements of snakes, that he has actually seen a male and female rabbit satisfy the s.e.xual instinct in that presence, a rabbit being seized by a snake when _in coitu_.

[41] "Habit and Intelligence," vol. i. p. 319.

[42] The reader may consult Huxley"s "Lessons in Elementary Physiology," p.

204.

[43] "Natural Selection," p. 350.

[44] Bivalve sh.e.l.l-fish are creatures belonging to the oyster, scallop, and c.o.c.kle group, _i.e._ to the cla.s.s Lamellibranchiata.

[45] The attempt has been made to explain these facts as owing to "manner and symmetry of growth, and to colour being incidental on the chemical nature of the const.i.tuents of the sh.e.l.l." But surely beauty depends on some such matters in _all_ cases!

[46] It has been suggested in opposition to what is here said, that there is no real resemblance, but that the likeness is "_fanciful!_" The denial, however, of the fact of a resemblance which has struck so many observers, reminds one of the French philosopher"s estimate of facts hostile to his theory--"Tant pis pour les faits!"

[47] Fifth Edition, p. 236.

[48] Mr. Smith, of the Entomological department of the British Museum, has kindly informed me that the individuals intermediate in structure are very few in number--not more than five per cent.--compared with the number of distinctly differentiated individuals. Besides, in the Brazilian kinds these intermediate forms are wanting.

[49] By accidental variations Mr. Darwin does not, of course, mean to imply variations really due to "chance," but to utterly indeterminate antecedents.

[50] "Origin of Species," 5th edition, p. 235.

[51] _I.e._ warm-blooded animals which suckle their young, such as apes, bats, hoofed beasts, lions, dogs, bears, weasels, rats, squirrels, armadillos, sloths, whales, porpoises, kangaroos, opossums, &c.

[52] "Journal of Anatomy and Physiology" (1868), vol. ii. p. 139.

[53] See "Ann. and Mag. of Nat. Hist." for August 1870, p. 140.

[54] See "Proceedings of the Royal Inst.i.tution," vol. v. part iv. p. 278: Report of a Lecture delivered February 7, 1868. Also "Quarterly Journal of the Geological Society," February 1870: "Contributions to the Anatomy and Taxonomy of the Dinosauria."

[55] "Proceedings of Geological Society," November 1869, p. 38.

[56] The archeopteryx of the oolite has the true carinate shoulder structure.

[57] "Proceedings of the Royal Inst.i.tution," vol. v. p. 279.

[58] This remark is made without prejudice to possible affinities in the direction of the Ascidians,--an affinity which, if real, would be irrelevant to the question here discussed.

[59] "Lectures on the Comp. Anat. of the Invertebrate Animals," 2nd edit.

1855, p. 619; and Todd"s "Cyclopaedia of Anatomy," vol. i. p. 554.

[60] See "Habit and Intelligence," vol. i. p. 321.

[61] A view recently propounded by Kowalewsky.

[62] "Natural Selection," p. 167.

[63] "Natural Selection," p. 173.

[64] Ibid. p. 177.

[65] "Malay Archipelago," vol. i. p. 439.

[66] "Natural Selection," p. 177.

[67] "Origin of Species," 5th edition, p. 166.

[68] Vol. ii. p. 280.

[69] See "Natural Selection," p. 64.

[70] The italics are not Mr. Wallace"s.