596 



PROF. F, WOOD JONES ON THE 



The third molar has 2 roots, of which the anterior is elongated 

 from side to side and shows a tendency to bifurcation ; possibly 



Text-figure 9. 



Alveolar cavities of the left upper molar series of Leporillus Jonesi . 



it represents the anterior and lingual roots of the second molar. 

 The root formula would therefore be 3. 3. 2. 



Lower Molars. 



Of the lower molars the large anterior member shows three 

 laminte on its occlusal surface, the second molar two laminae, and 

 the third also two. The root -pattern shows the same reception 

 of part of the crown into a depressed area of the jaw as is seen 

 in the case of the upper teeth. (See text-fig. 10, B.) Each 

 tooth is provided with 2 roots, and anterior rounded root, and a 

 posterior one elongate from side to side. In the case of the first 

 molar there is a tendency towards lateral bifurcation of the 

 posterior root. The lower root-formula is therefore 2. 2. 2. 



The rats whose remains have gone in such countless numbers 

 to constitute the bone-doposits in the Buckalowie caves, had the 

 molars sunk into the jaw in the same fashion as is seen in the 

 Franklin Island Leporillus. They had the same root-formula 

 above and below (see text-fig. 2 and compare text-figs. 9 & 10) ; 



