[83] “The Speech of Monkeys.”
[84] “Scientific Lectures,” pp. 112, 118.
[85] Nature, vol. vii., p. 443.
[86] “The Senses of Animals,” p. 277.
[87] “Mental Evolution in Man,” p. 100.
[88] Op. cit., p. 175.
[89] Compare chap. xiii., on “The Perception of Relations,” in my “Introduction to Comparative Psychology.”
[90] Nineteenth Century, May, 1897, pp. 793–807.
[91] Sharp, “Insects,” part ii., p. 147.
[92] Nature, vol. lxii., p. 253 (July 12, 1900).