[103] This animal belongs to the order Primates, which includes man, the apes, and the lemurs. The lemurs are the lower kinds of the order, and differ much from the apes. They have their head-quarters in the Island of Madagascar. The aye-aye is a lemur, but it differs singularly from all its congeners, and still more from all apes. In its dentition it strongly approximates to the rodent (rat, squirrel, and guinea-pig) order, as it has two cutting teeth above, and two below, growing from permanent pulps, and in the adult condition has no canines. [104] _North British Review_, New Series, vol. vii., March 1867, p. 282. [105] "Habit and Intelligence," vol. i. p. 75. [106] "Habit and Intelligence," vol. i. p. 202. [107] "Comparative Physiology," p. 214, note. [108] See _Nature_, June and July 1870, Nos. 35, 36, and 37, pp. 170, 193, and 219. [109] "Natural Selection," p. 293. [110] "Animals and Plants under Domestication," vol. i. pp. 289-295. [111] "Origin of Species," 5th edition, 1869, p. 45. [112] Ibid. p. 13. [113] "Animals and Plants under Domestication," vol. i. p. 115. [114] Ibid. vol. i. p. 114. [115] Ibid. vol. i. p. 243. [116] Ibid. vol. ii. p. 361. [117] Ibid. vol. ii. p. 16. [118] "Animals and Plants under Domestication," vol. ii. p. 57. [119] This has been shown by my late friend, Mr. H. N. Turner, jun., in an excellent paper by him in the "Proceedings of the Zoological Society for 1849," p. 147. The untimely death, through a dissecting wound, of this most promising young naturalist, was a very great loss to zoological science. [120] "Animals and Plants under Domestication," vol. ii. p. 189. [121] "Origin of Species," 5th edition, 1839, p. 115. [122] Ibid. p. 322. [123] Ibid. p. 314. [124] "Animals and Plants under Domestication," vol. ii. p. 104. [125] _North British Review_, New Series, vol. vii., March 1867, p. 317. [126] "Origin of Species," 5th edition, 1869, p. 212. [127] See also the _Popular Science Review_ for July 1868. [128] A bird with a keeled breast-bone, such as almost all existing birds possess. [129] "Anatomy of Vertebrates," vol. iii. p. 792. [130] Ibid. p. 793. [131] As a tadpole is the _larval form_ of a frog. [132] As Professor Huxley, with his characteristic candour, fully admitted in his lecture on the Dinosauria before referred to. [133] "Transactions of the Geological Society of Glasgow," vol. iii. [134] "Origin of Species," 5th edition, p. 354. [135] See his address to the Geological Society, on February 19, 1869. [136] See _Nature_, vol. i. p. 399, February 17, 1870. [137] Ibid. vol. i. p. 454. [138] "Habit and Intelligence," vol. i. p. 344. [139] "Habit and Intelligence," vol. i. p. 345. [140] "Origin of Species," 5th edition, p. 353. [141] "Origin of Species," 5th edition, p. 381. [142] "Origin of Species," 5th edition, 1869, p. 463. [143] See his Catalogue of Acanthopterygian Fishes in the British Museum, vol. iii. p. 540.