[31] According to the observations of M. Gerbe; see Günther’s ‘Record of Zoolog. Literature,’ 1865, p. 194. [32] Cuvier, ‘Règne Animal,’ vol. ii. 1829, p. 242. [33] See Mr. Warington’s most interesting description of the habits of the _Gasterosteus leiurus_, in ‘Annals and Mag. of Nat. Hist.’ November, 1855. [34] Prof. Wyman, in ‘Proc. Boston Soc. of Nat. Hist.’ Sept. 15, 1857. Also W. Turner, in ‘Journal of Anatomy and Phys.’ Nov. 1, 1866, p. 78. Dr. Günther has likewise described other cases. [35] Yarrell, ‘Hist. of British Fishes,’ vol. ii. 1836, p. 329, 338. [36] Dr. Günther, since publishing an account of this species in ‘The Fishes of Zanzibar,’ by Col. Playfair, 1866, p. 137, has re-examined the specimens, and has given me the above information. [37] The Rev. C. Kingsley, in ‘Nature,’ May, 1870, p. 40. [38] Bell, ‘History of British Reptiles,’ 2nd edit. 1849, p. 156-159. [39] Bell, ibid. p. 146, 151. [40] ‘Zoology of the Voyage of the “Beagle,”’ 1843. “Reptiles,” by Mr. Bell, p. 49. [41] ‘The Reptiles of India,’ by Dr. A. Günther, Ray Soc. 1864, p. 413. [42] Bell, ‘History of British Reptiles,’ 1849, p. 93. [43] J. Bishop, in ‘Todd’s Cyclop. of Anat. and Phys.’ vol. iv. p. 1503. [44] Bell, ibid. p. 112-114. [45] Mr. C. J. Maynard, ‘The American Naturalist,’ Dec. 1869, p. 555. [46] See my ‘Journal of Researches during the Voyage of the “Beagle,”’ 1845, p. 384. [47] ‘Travels through Carolina,’ &c., 1791, p. 128. [48] Owen, ‘Anatomy of Vertebrates,’ vol. i. 1866, p. 615. [49] Sir Andrew Smith, ‘Zoolog. of S. Africa: Reptilia,’ 1849, pl. x. [50] Dr. A. Günther, ‘Reptiles of British India,’ Ray Soc. 1864, p. 304, 308. [51] Owen, ‘Anatomy of Vertebrates,’ vol. i. 1866, p. 615. [52] The celebrated botanist Schleiden incidently remarks (‘Ueber den Darwinismus: Unsere Zeit,’ 1869, s. 269), that Rattle-snakes use their rattles as a sexual call, by which the two sexes find each other. I do not know whether this suggestion rests on any direct observations. These snakes pair in the Zoological Gardens, but the keepers have never observed that they use their rattles at this season more than at any other. [53] “Rambles in Ceylon,” ‘Annals and Mag. of Nat. Hist.’ 2nd series, vol. ix. 1852, p. 333. [54] ‘Westminster Review,’ July 1st, 1867, p. 32. [55] Mr. N. L. Austen kept these animals alive for a considerable time, see ‘Land and Water,’ July, 1867, p. 9. [56] All these statements and quotations, in regard to Cophotis, Sitana and Draco, as well as the following facts in regard to Ceratophora, are Footnote: taken from Dr. Günther’s magnificent work on the ‘Reptiles of British India,’ Ray Soc. 1864, p. 122, 130, 135. [57] Bell, ‘History of British Reptiles,’ 2nd edit. 1849, p. 40.