• 1
    A study has been made of post-natal growth changes in the basicranial axis of the baboon (thirty-five skulls), the rhesus monkey (forty-eight skulls), the orang-utan (thirty-nine skulls), the gorilla (sixty-five skulls) and the chimpanzee (sixty-six skulls).
  • 2
    In both monkeys and apes:
  • a. 
    The basicranial axis and its anterior extension to the nasion continue to grow until maturity is reached.
  • b. 
    The posterior extension to the opisthion attains adult size by the time the first permanent molars are in line.
  • c. 
    The spheno-ethmoidal angle continues to increase throughout post-natal development.
  • d. 
    The foramino-basal angle becomes more acute as the permanent teeth erupt.
  • 3
    The slight differences that exist between the growth patterns of the basicranial axes of monkeys, apes and man can be related to variations in relative size of the cranium and facial skeleton.