ネズミ類の臼歯の型と発育について : I.短歯性臼歯

概要

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1. The developmental prcesses of brachyodont molars in the albino rat and those in the golden hamster, were compared as part of syudy of the molar types in the murids. 2. The time of the first appearance of molar germs sems to be nearly similae in the two species but it is fairly earlier in the hamster when the length of the prenatal period is taken into account. 3. Odontogenesis of the molars progresses faster in the cuspidal parts and delays in the basal parts. In the hamster the development of dental roots of the first molar begins before the 5th day after birth and finishes on about 20th day. While in the rat it begins on about 18th day and finishes far later. 4. The first molar erupts on about 10th day after birth in the hamster, and on about 18th day in the rat. From these facts it is concluded that the molars of the hamster and those of the rat, which are both bracyodont, are remarkably different in the rate of development.
1962-03-15