DENTAL CHARACTERS OF AUSTRALIAN RATS. 



593 



molar. If the line of the palatal suture, or the origin of the 

 posterior zygoma root, should prove to be at all stable points in 

 cranial architecture, it would look as though the anterior lamina 

 of the upper anterior molar occupied somewhat the same 

 anatomical position as the whole of the anterior molar in more 

 typical forms. 



E.ATTUS. 



(1) R. greyi. Specimens from Mount Compass, South Australia. 

 Identity established by Mr. Oklfield Thomas (Ann. & Mag. Nat. 

 Hist, series 9, vol. viii. p. 425, October 1921). 



Upper Molcii's. 



The crown-pattern of the upper molars is shown in text- 

 ifig. 6, A, 



Text-figure 6. 



Left upper molar series of Mattus greyi. A, showing the occlusal surface ; 

 and B, the alveolar cavities. 



It is typical and needs no description. 



The roots are small, their alveoli being a series of clean-cut 



