ORDER MARSUPIALIA. 1 283 



species, and appears to have been allied in many respects to the 

 Wombats, although presenting several of the dental characters of the 



next family. The dental formula is /. -. C. -, Pm. -, M. - : and 



J 1 o 1 4 



it appears that, at least normally, there was no deciduous milk- 

 molar. The cheek-teeth are rooted ; the crowns of the true molars 

 carrying two simple transverse ridges. The cranium (fig. 1154) 

 presents a very singular contour, the nasals being transversely ex- 

 panded ; and the mandible differs from that of the Phascolomyidce, 



Fig. 1 1 54. — Left lateral view of the skull of Nototherium Mitchelli ; from the Pleistocene 

 of Australia. One-sixth natural size. (After Owen.) 



by the absence of a pit or perforation in the masseteric fossa (fig. 

 1 1 54). The limb-bones appear, however, to have resembled those 

 of the latter family ; the humerus having a distal foramen, and 

 being evidently adapted for fossorial habits, although it is difficult 

 to believe that an animal of such comparatively large bulk could 

 have lived in burrows. 



Family Diprotodontid^e. — The genus Difirotodon, of the Aus- 

 tralian Pleistocene, is the sole representative of this extinct family, 

 and the type species (fig. 1155) is the largest known member of 

 the order ; its bulk being fully equal to that of a large Rhinoceros. 

 The dental formula is the same as that of Nototherium ; and the 

 structure of the cheek-teeth of the two genera is also very similar, 

 although the lower true molars of Diprotodon have no median 

 longitudinal bridge. In the incisors of this genus the first pair are 



ported by sufficient evidence. A small Nototheroid from Queensland has re- 

 ceived the preoccupied name Owenia. 



