1. H. KLAATSCH, “The Skull of the Australian Aboriginal” (_Reports from the Pathological Laboratory of the Lunacy Department, New South Wales Government_, vol. i, part iii [Sydney, 1908], pp. 3-167); “Der primitive Mensch der Vergangenheit und Gegenwart” (_Verhandlungen der Gesellschaft deutscher Naturforscher und Aerzte_, 80 Vers. zu Cöln, part i, p. 95); Anatomische Hefte, 1902. 2. C. H. STRATZ DEN HAAG, “Das Problem der Rasseneinteilung der Menschheit” (_Archiv für Anthropologie_, N. S., vol. i, pp. 189 _et seq._). 3. OTTO SCHOETENSACK, “Die Bedeutung Australiens für die Heranbildung des Menschen aus einer niederen Form” (_Zeitschrift für Ethnologie_, vol. xxxiii [1901], pp. 127 _et seq._). 4. D. J. CUNNINGHAM, “The Lumbar Curve in Man and Apes” (_Cunningham Memoirs_ [Dublin, 1886]). Page 24. 1. KARL PEARSON, “On the Relationship of Intelligence to Size and Shape of Head, and to other Physical and Mental Characters” (_Biometrika_, vol. v, pp. 136 _et seq._). 2. L. MANOUVRIER, “Les aptitudes et les actes dans leurs rapports avec la constitution anatomique et avec le milieu extérieur” (_Bulletins de la Société d’Anthropologie de Paris_, 4^o series, vol. i [1890], pp. 918 _et seq._). Page 25. P. TOPINARD, Éléments d’Anthropologie générale, p. 620. The value for African negroes is here very small. Another series quoted by Topinard (_Ibid._, p. 622), consisting of 100 skulls of each group, gives the following averages: Parisians, 1551 cc.; Auvergnats, 1585 cc.; African negroes, 1477 cc.; New Caledonians, 1488 cc. (a misprint in Topinard’s book makes this appear as 1588 cc.). Page 26. 1. L. MANOUVRIER, “Sur l’interprétation de la quantité dans l’encéphale” (_Mémoires de la Société d’Anthropologie de Paris_, 2d series, vol. iii, pp. 284, 277, 281). 2. F. GALTON, “Head Growth in Students at Cambridge” (_Journal of the Anthropological Institute of Great Britain and Ireland_, vol. xviii, p. 156). Page 27. A. DA COSTA FERRAIRA, “La capacité du crâne chez les Portugais” (_Bulletins et Mémoires de la Société d’Anthropologie de Paris_, Série V, vol. iv [1903], pp. 417 _et seq._). Page 28. H. H. DONALDSON, The Growth of the Brain (1895); RAYMOND PEARL, “Variation and Correlation in Brain-Weight” (_Biometrika_, vol. iv, pp. 13 _et seq._). Page 29. FRANKLIN P. MALL. See note 2 to p. 18. Page 36. R. H. LOCK, Recent Progress in the Study of Variation, Heredity and Evolution (1906), pp. 73 _et seq._; A. L. BOWLEY, Elements of Statistics (1901). Page 41. R. WIEDERSHEIM, Der Bau des Menschen (4th ed., 1908); The Structure of Man an Index to his Past History (1895). Page 44.