The Premaxilla and the Ancestry of Man

Abstract

PROF. WOOD JONES' theory of human evolution based on the premaxillary bone is, of course, well known¹. It depends on his assumption that it is legitimate to infer the phylogenetic antiquity of a morphological character by noting the time of its ontogenetic appearance. However, attention is invited to Ashley-Montagu's comprehensive study on the premaxilla of the primates², in which the author reports that the apical portion of the premaxilla may in some cases be observed on the facial aspect of the late fÅ"tal and infant human skull, quite clearly separated from the maxilla by a distinct suture. I have recently had the opportunity of studying the original fossil Australopithecine material in South Africa, and gave particular consideration to the architecture of the upper jaw. There appeared to be no feature here which contradicts the conclusions put forward by Prof. R. A. Dart and Dr. R. Broom that the Australopithecinæ do indeed give very important information regarding the primate forms which were ancestral to Homo.