[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 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.
[58] For Proctotretus see ‘Zoology of the Voyage of the “Beagle:” Reptiles,’ by Mr. Bell, p. 8. For the Lizards of S. Africa, see ‘Zoology of S. Africa: Reptiles,’ by Sir Andrew Smith, pl. 25 and 39. For the Indian Calotes, see ‘Reptiles of British India,’ by Dr. Günther, p. 143.
[59] ‘Ibis,’ vol. iii. (new series) 1867, p. 414.