Problems relating to the teeth of the earlier forms of prehistoric man / by Arthur Keith.

  • Arthur Keith
Date:
1913
Catalogue details

Licence: In copyright

Credit: Problems relating to the teeth of the earlier forms of prehistoric man / by Arthur Keith. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    close structural relationship between man and the great anthropoids and the manner in which the canine tooth is developed and formed in modern man. In fig. 11 is represented various degrees of the canine development met with in the higher primates. The teeth are drawn to scale with the palate placed in true profile. Four individuals are represented in fig. 11, a native Australian with a well-developed dentition, a female chimpanzee, a male chimpanzee, and a gorilla. These individuals represent various degrees in the plenal development of the canine region of the palate. The changes in this region—both progressive and retrogressive—proceed independently of the changes affecting the molar region. The molar series of the Piltdown mandible has a total length of about 36 mm.; the three molars were thus of moderate size, but the teeth of the canine region must have reached dimensions far Fig. 10. Two views of the third upper right molar of Pithecanthropus (after Dubois). The squares represent centimetres. beyond any human dentition yet known. Amongst higher living primates the teeth of the canine region of the jaw find their maximum development in the male gorilla. In the specimen shown in fig. 11 the teeth of the anterior or canine region extend in an antero-posterior or sagittal direction—from the crowns of the mesial incisors in front to a line joining the distal margins of the second premolars for a distance of 52 mm. {see fig. 11); in the male chimpanzee the extent is 45 mm.; in the female chimpanzee 57 mm.; in the Australian palate shown in fig. 11, 27 mm. Using the same terms as before, it may be said that in the male gorilla caninism reaches a supra-plenal degree ; in the Australian, an infra-plenal development; while in the female chimpanzee a mean or plenal phase is represented. The effect of caninism is not confined to the canine teeth alone; the first premolar is affected in every phase of
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