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Abstract

The purpose of this study is to compara differences of the cranial measurement , tooth counts and tooth morphology in Onychodactylus japonicus from Shizuoka (Common type) and those from Tochigi (Tohoku type).The following results were obtained. 1) Cranial measurements show that the Common type is longer than the Tohoku type in premaxillary breadth, mandibular dental arch length, palatal length and maximum breadth of the vomer. The correlation index shows that the Common type has a lower value in palatal length and maxillary dental arch width.2) Tooth counts of the Common type show about the same number in the premaxilla as in the Tohoku type. The tooth count of the Common type is larger than the Tohoku type in other sites.3) Tooth form and attachment are similar in the two types . Labial and buccal tooth cusps in the Common type are semicircular, while in the Tohoku type they are flat . Palatal and lingual cusps in the Common type are cone shaped , while in the Tohoku type they are of flattened cone shape.