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Show 410 MR. C S. TOMES ON THE TEETH OF NOTORYCTES. [-Apr. 6, marsupial plan." This is to a certain extent true ; but yet they differ from all other teeth with which I a m acquainted, and they are interesting in respect of the question of the food of this creature, which is unfortunately not known with exactitude. Dr. Stirling found the remains of ants in the digestive tract; but in confinement these animals would not eat ants, though one did eat a large soft grub, tbe larval form of a longicorn beetle, or perhaps of a lepido-pterous insect, and another ate a piece of bread. The structure of the teeth would seem to indicate that its food is not very hard. In Dr. Stirling's figures of the grinding-surfaces of the molar teeth it is shown that the middles are worn into concavities, and that the retention of the cuspidate form is not due to the persistence of the sharp enamelled cusps, as is the case in Insectivora generally, but that it is due to the upstanding of the edges. This is well seen in the drawing (fig. 1), which shows the enamel absent (i. e. worn through) on the masticating surfaces, but remaining and projecting a little all round the circumference of the tooth, so that an area of dentine surrounded by an upstanding ring of mitfS&-~I~.-~«v^>-'i.. ,•-... The last two lower molars of Notoryctes, in situ, x l 4 ; tbe ascending piece of bone to tbe right of the figure is a portion of the coronoid process. In tbe front of the two teetb tbe pulp-cavity still persists, in tbe other it is apparently nearly obliterated. Two obsolete vascular canals are to be seen near the surface of tbe dentine. enamel is used for mastication. This condition of severe wear appears not to be very common in insectivorous mammals, whose teeth generally long retain their enamel and bristling cusps; but it may be seen in old specimens of Perameles and in some true |