[199] Quoted by Mr. Lawson Tait in his “Law of Natural Selection,”—‘Dublin Quarterly Journal of Medical Science,’ Feb. 1869. Dr. Keller is likewise quoted to the same effect.
[200] Owen, ‘Anatomy of Vertebrates,’ vol. iii. p. 71.
[201] ‘Quarterly Review,’ April, 1869, p. 392.
[202] In Hylobates syndactylus, as the name expresses, two of the digits regularly cohere; and this, as Mr. Blyth informs me, is occasionally the case with the digits of H. agilis, lar, and leuciscus.
[203] Brehm, ‘Thierleben,’ B. i. s. 80.
[204] “The Hand, its mechanism,” &c. ‘Bridgewater Treatise,’ 1833, p. 38.
[205] Häckel has an excellent discussion on the steps by which man became a biped: ‘Natürliche Schöpfungsgeschichte,’ 1868, s. 507. Dr. Büchner (‘Conférences sur la Théorie Darwinienne,’ 1869, p. 135) has given good cases of the use of the foot as a prehensile organ by man; also on the manner of progression of the higher apes to which I allude in the following paragraph: see also Owen (‘Anatomy of Vertebrates,’ vol. iii. p. 71) on this latter subject.
[206] “On the Primitive Form of the Skull,” translated in ‘Anthropological Review,’ Oct. 1868, p. 428. Owen (‘Anatomy of Vertebrates,’ vol. ii. 1866, p. 551) on the mastoid processes in the higher apes.
[207] ‘Die Grenzen der Thierwelt, eine Betrachtung zu Darwin’s Lehre,’ 1868, s. 51.
[208] Dujardin, ‘Annales des Sc. Nat.’ 3rd series, Zoolog. tom. xiv. 1850, p. 203. See also Mr. Lowne, ‘Anatomy and Phys. of the Musca vomitoria,’ 1870, p. 14. My son, Mr. F. Darwin, dissected for me the cerebral ganglia of the Formica rufa.