410 MB. C. S. TOMES ON THE TEETH OF NOTOKYCTES. [Apr. 6, 



marsupial plan."' This is to a certain extent true ; but yet they 

 differ from all other teeth with which I am 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, the larval form of a longicorn beetle, or perhaps of a lepido- 

 pterous insect, and another ate a piece of bread. Tlie structure of 

 the teeth would seem to indicate that its food is not very hard. 



In Dr. Stirling's figures of the grindiug-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 per- 

 sistence 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 remain- 

 ing and projecting a little all round the circumference of the tooth, 

 so that an area of dentine surrounded by an upstanding ring of 



The last two lower molars of Notonjcics, in siHi, xl4; the ascending piece 

 of bone to the right of the figure is a portion of the coronoid process. 

 In the front of the two teeth the pulp-cavity still persists, in the other it is 

 apparently nearly obliterated. Two obsolete vascular canals are to be seen 

 near the surface of the 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 



