Note 12 — Chapter I
Reading edition
For the relation between chin formation and power of speech, see E. Walkhoff, "Der Unterkiefer der Anthropomorphen und des Menschen in seiner funktionellen Entwicklung und Gestalt," E. Selenka, Menschenaffen, 1902; H. Obermaier, Der Mensch der Vorzeit, 1912, p. 362; and W. Wright, "The Mandible of Man from the Morphological and Anthropological points of view," Essays and Studies presented to W. Ridgeway, 1913.