June 19 and July 17, 1869.

[159] I have given authorities for these several statements in my 'Variation of Animals under Domestication,' vol. ii. p.

297-300. Dr. Jaeger, "Ueber das Langenwachsthum der Knochen,"

'Jenaischen Zeitschrift,' B. v. Heft i.

[160] 'Investigations,' &c. By B. A. Gould, 1869, p. 288.

[161] 'Saugethiere von Paraguay,' 1830, s. 4.

[162] 'History of Greenland,' Eng. translat. 1767, vol. i. p.

230.

[163] 'Intermarriage.' By Alex. Walker, 1838. p. 377.

[164] 'The Variation of Animals under Domestication,' vol. i.

p. 173.

[165] 'Principles of Biology,' vol. i. p. 455.

[166] Paget, 'Lectures on Surgical Pathology,' vol. i. 1853, p.

209.

[167] 'The Variation of Animals under Domestication,' vol. ii.

p. 8.

[168] 'Saugethiere von Paraguay,' s. 8, 10. I have had good opportunities for observing the extraordinary power of eyesight in the Fuegians.' See also Lawrence ('Lectures on Physiology,'

&c., 1822, p. 404) on this same subject. M. Giraud-Teulon has recently collected ('Revue des Cours Scientifiques,' 1870, p.

625) a large and valuable body of evidence proving that the cause of short-sight, "_C'est le travail a.s.sidu, de pres._"

[169] Prichard, 'Phys. Hist. of Mankind,' on the authority of Blumenbach, vol. i. 1851, p. 311; for the statement by Pallas, vol. iv. 1844, p. 407.

[170] Quoted by Prichard, 'Researches into the Phys. Hist. of Mankind,' vol. v. p. 463.

[171] Mr. Forbes' valuable paper is now published in the 'Journal of the Ethnological Soc. of London,' new series, vol.

ii. 1870, p. 193.

[172] Dr. Wilckens ('Landwirthschaft. Wochenblatt,' No. 10, 1869) has lately published an interesting essay shewing how domestic animals, which live in mountainous regions, have their frames modified.

[173] 'Memoire sur les Microcephales,' 1867, p. 50, 125, 169, 171, 184-198.

[174] See Dr. A. Farre's well-known article in the 'Cyclop. of Anat. and Phys.' vol. v. 1859, p. 642. Owen 'Anatomy of Vertebrates,' vol. iii. 1868, p. 687. Prof. Turner in 'Edinburgh Medical Journal,' Feb. 1865.

[175] 'Annuario della Soc. dei Naturalisti in Modena,' 1867, p.

83. Prof. Canestrini gives extracts on this subject from various authorities. Laurillard remarks, that as he has found a complete similarity in the form, proportions, and connexion of the two malar bones in several human subjects and in certain apes, he cannot consider this disposition of the parts as simply accidental.

[176] A whole series of cases is given by Isid. Geoffroy St.-Hilaire, 'Hist. des Anomalies,' tom. iii. p. 437.

[177] In my 'Variation of Animals under Domestication' (vol.

ii. p. 57) I attributed the not very rare cases of supernumerary mammae in women to reversion. I was led to this as a _probable_ conclusion, by the additional mammae being generally placed symmetrically on the breast, and more especially from one case, in which a single efficient mamma occurred in the inguinal region of a woman, the daughter of another woman with supernumerary mammae. But Prof. Preyer ('Der Kampf um das Dasein,' 1869, s. 45) states that _mammae erraticae_ have been known to occur in other situations, even on the back; so that the force of my argument is greatly weakened or perhaps quite destroyed.

With much hesitation I, in the same work (vol. ii. p. 12), attributed the frequent cases of polydactylism in men to reversion. I was partly led to this through Prof. Owen's statement, that some of the Ichthyopterygia possess more than five digits, and therefore, as I supposed, had retained a primordial condition; but after reading Prof. Gegenbaur's paper ('Jenaischen Zeitschrift,' B. v. Heft 3, s. 341), who is the highest authority in Europe on such a point, and who disputes Owen's conclusion, I see that it is extremely doubtful whether supernumerary digits can thus be accounted for. It was the fact that such digits not only frequently occur and are strongly inherited, but have the power of regrowth after amputation, like the normal digits of the lower vertebrata, that chiefly led me to the above conclusion. This extraordinary fact of their regrowth remains inexplicable, if the belief in reversion to some extremely remote progenitor must be rejected. I cannot, however, follow Prof. Gegenbaur in supposing that additional digits could not reappear through reversion, without at the same time other parts of the skeleton being simultaneously and similarly modified; for single characters often reappear through reversion.

[178] 'Anatomy of Vertebrates,' vol. iii. 1868, p. 323.

[179] 'Generelle Morphologie,' 1866, B. ii. s. clv.

[180] Carl Vogt's 'Lectures on Man,' Eng. translat. 1864, p.

151.

[181] C. Carter Blake, on a jaw from La Naulette, 'Anthropolog.

Review,' 1867, p. 295. Schaaffhausen, ibid. 1868, p. 426.

[182] 'The Anatomy of Expression,' 1844, p. 110, 131.

[183] Quoted by Prof. Canestrini in the 'Annuario,' &c., 1867, p. 90.

[184] These papers deserve careful study by any one who desires to learn how frequently our muscles vary, and in varying come to resemble those of the Quadrumana. The following references relate to the few points touched on in my text: Proc. Royal Soc. vol. xiv. 1865, p. 379-384; vol. xv. 1866, p. 241, 242; vol. xv. 1867, p. 544; vol. xvi. 1868, p. 524. I may here add that Dr. Murie and Mr. St. George Mivart have shewn in their Memoir on the Lemuroidea ('Transact. Zoolog. Soc.' vol. vii.

1869, p. 96), how extraordinarily variable some of the muscles are in these animals, the lowest members of the Primates.

Gradations, also, in the muscles leading to structures found in animals still lower in the scale, are numerous in the Lemuroidea.

[185] Prof. Macalister in 'Proc. R. Irish Academy,' vol. x.

1868, p. 124.

[186] Prof. Macalister (ibid. p. 121) has tabulated his observations, and finds that muscular abnormalities are most frequent in the fore-arms, secondly in the face, thirdly in the foot, &c.

[187] The Rev. Dr. Haughton, after giving ('Proc. R. Irish Academy,' June 27, 1864, p. 715) a remarkable case of variation in the human _flexor pollicis longus_, adds, "This remarkable example shews that man may sometimes possess the arrangement of tendons of thumb and fingers characteristic of the macaque; but whether such a case should be regarded as a macaque pa.s.sing upwards into a man, or a man pa.s.sing downwards into a macaque, or as a congenital freak of nature, I cannot undertake to say."

It is satisfactory to hear so capable an anatomist, and so embittered an opponent of evolutionism, admitting even the possibility of either of his first propositions. Prof.

Macalister has also described ('Proc. R. Irish Acad.' vol. x.

1864, p. 138) variations in the _flexor pollicis longus_, remarkable from their relations to the same muscle in the Quadrumana.

[188] The authorities for these several statements are given in my 'Variation of Animals under Domestication,' vol. ii. p.

320-335.

[189] This whole subject has been discussed in chap. xxiii.

vol. ii. of my 'Variation of Animals and Plants under Domestication.'

[190] See the ever memorable 'Essay on the Principle of Population,' by the Rev. T. Malthus, vol. i. 1826, p. 6, 517.

[191] 'Variation of Animals and Plants under Domestication,'

vol. ii. p. 111-113, 163.

[192] Mr. Sedgwick, 'British and Foreign Medico-Chirurg.

Review,' July, 1863, p. 170.

[193] 'The Annals of Rural Bengal,' by W. W. Hunter, 1868, p.

259.

[194] 'Primitive Marriage,' 1865.