5-16 MR. O. THOMAS ON LAGORCHESTES FASCIATUS. [DeC. 7, 



its lower side corresponding to the chin, no trace of such a prominence 

 being present in any of the other genera. 



In natural correlation to this structure of the jaw, the lower 

 incisors themselves have not the sharp inwardly projecting edges 

 characteristic of those of the other Kangaroos, and are merely 

 approximated to each other by their flat inner surfaces ; the trans- 

 verse sections of the incisors of the two forms (figs. 4 and 10) show 

 this difference better than any description. 



The incisors and symphysis thus indicating a difference in the 

 motion and use of the mandible, we should naturally expect an 

 appreciable change in the shape of those parts of it by which it is 

 attached and moved, and we therefore find, first, that the coronoid 

 process possesses the very unusual character of having its anterior 

 edge slightly concave in its upper half, all other Kangaroos having 

 this part evenly convex ; and, secondly, the condyle, instead of 

 having its length and breadth much about equal, is very much 

 broader than long, and is provided with a broad, flat, supplementary 

 internal process (compare figs. 5 and 11). 



Canines, present in Lagorchestes, are, as in the majority of the 

 Macropodidse, wholly absent in Lagostrophus. 



The two premolars of Lagostrophus, i. e. the smaller anterior deci- 

 duous one, pm^ of the typical dentition, and the larger permanent one, 

 or pm'' (fig. 7), are both broad and flattened, their posterior decidedly 

 greater than their anterior diameters, with well-developed internal 

 edges, and with four or five shallow vertical grooves on their external 

 surfaces. The premolars therefore correspond with the incisors in 

 being broader and more flattened than is usual ; but the difference, at 

 least in comparison with certain of the broader-toothed species, such as 

 Macropits brachyurus, Quoy and Gaim ., or Lagorchestes conspicillatus, 

 Gould, is by no means so striking as in the case of the incisors. 



The molars appear to be precisely similnr to those of Lagorchestes 

 and the other smaller members of the MacropodincB. 



The general shape of the skull (fig. 1) presents nothing very 

 remarkable, except that, owing to the approximation of the two 

 incisor series to each other, the premaxillpe bearing them are very 

 much narrower transversely than usual, and therefore give a peculiar 

 slender and pointed appearance to the muzzle. 



With regard to the external characters, we have first to note that 

 the rhinarium, notwithstanding the statements of Gould and Water- 

 house, is really practically naked, as in the Wallabies, and is not 

 hairy as in Lagorchestes \ The hair, in fact, only grows down the 

 centre of the nose to the level of the superior internal angle of the 

 nostrils, leaving the whole of the front of the nasal septum bare. 



The hind feet, instead of being short-haired as in Lagorchestes, 

 are covered with long bristly hairs, very much as in Petrogale, 

 these bails nearly entirely covering up the narrow naked sole, and 

 hiding the short, but strong and conical, central hind claws. 



' Even in Lagorchestes the laairiuess is very variable, L. conspicillatus having 

 * very much less hairy muzzle than L. leporoides, the type of the genus. 



