VIII—The development and morphology of the teeth of Ornithorhynchus *

Abstract

Though tooth development in the mammals has been extensively studied, I had several objects in view when I decided to investigate the details of tooth development in Ornithorhynchus. The following are among the more important considerations which determined me to undertake this work. 1— Early Stages in the Differentiation the Dental Lamina and the Formation of the Enamel Organ The structure of the dental lamina and the stages in the early differentiation of the enamel organ have been carefully examined in representative groups by many observers, and by the beginning of this century the histological appearances of the dental lamina and its adnexa were well known. Yet the significance of some of the structures which are seen in the early stages of tooth development is still uncertain, and widely divergent views have been expressed, not only as to the interpretation of such structures in the individual animal, but also as to their possible value in the light of phylogenetic recapitulation.