Title An Electron Microscope Study of Asiatic Elephant Tooth Enamel

An electron microscopical observation of the replicas of poJished and etched surface of asiatic elephant tooth enamel was carried out in order to examifie the histological differences and varieties of enamel microstructure in relation to the position within an individual molar and the order of eruption as to five molars. Through the observation the histological differences were found to be almost negligible for the purpose of the correlation and identification of fossil proboscidea. Three different layers of the enamel were discriminated and one of them, intermediate layer, was recommended as the representative of the typical specific patterns. Resum6 Une observation par le microscope 61ectronique des r6pliques de la surface polie et corrod6e de 1'6mail de dent des 616phants d'Asie a 6te ex6cut6e afin d'examiner les diff6rences histologiques et les vari6t6s de la microstructure de 1'6mail dans leur rapports avec la position en dega d'une molaire individuelle et 1'ordre d'6ruption de cinq molaires. Cette observation nous a amen6 a aMrmer que les differences histologique 6talnet presque n6gligeable pour le but de la correlation et de 1'identification de proboscides fossils. Trois diff6rentes couches de 1'6mail ont 6t6 discrimin6es et une d'eux: une couche interm6diaire a 6te recommand6e comme la forme repr6sentative de 1'6spece. Introduction Morphological evolutional trend of the mammalian teeth has been one of the most interesting subjects in the field of vertebrate paleontology, and notable investigations have been done both in details and perspectively. Then the writer is going to take up this problem from another view-point, the histological, and the teeth of fossil proboscidea are used here as thematerials ofinvestigation because of its relative abundance in the numbers of species and quantities in Japan. * Department ofAnatomy, School of Dentistry, Tokyo Me dical and Dental University.