[20] W. E. Ling Roth, North Queensland Ethnology, Bulletin V. § 81.
[21] A. Keith, The Antiquity of Man, p. 134.
[22] M. A. Czaplicka, My Siberian Year, p. 230.
[23] Ripley, The Races of Europe, pp. 76-7.
[24] Darwin, Animals and Plants under Domestication, Pop. ed., II. p. 308.
[25] The contents of this section lie outside my own studies, and have been taken from various books of Geology and Palæontology: I must especially mention Prof. Osborne’s Age of Mammals (1910) and Prof. Scott’s Land Mammals in the Western Hemisphere (1913). I have also profited by inspecting the Palæontological Gallery at South Kensington with the help of its excellent Guide-Book.
[26] A. Keith, The Human Body, p. 58.
[27] Travels and Researches in Western Africa, ch. vii.
[28] See The Antiquity of Man, by Arthur Keith.
[29] Malay Archipelago, pp. 46-7.