1900.] FOSSIL MABSITPIAL FROM TASMANIA. 781 



meatus is directed outwards and a little forwards. The glenoid 

 cavity is placed neither very high nor very low in regard to the 

 base of the skull ; it is higher than in the Dasyuridae, where it is 

 more nearly on a level with the base of the skull, and somewhat 

 lower than in the Phalangeridse, though it approximates more 

 nearly to the position in the latter. 



The frontals show only a faint trace of a postfroutal process 

 tending to bound posteriorly an orbital space ; their greatest width 

 occurs in the cranial and not in the facial portion — a feature which 

 is the reverse of that which is characteristic of marsupials, amongst 

 whom the broadest part of the frontal is characteristically found 

 in the facial part of the skull. Dorsally the frontal region 

 is marked by a concavity of a V-shape, sharply outlined. This 

 concavity is nothing like so wide nor so extensive in length as it 

 is in Cuscus, TricJwsurus, and Psmdochirus, from which it differs 

 markedly in appearance and very much more resembles that of 

 Dasyurus. Its posterior end, which practically corresponds in 

 position with that of the least intertemporal width, is marked by 

 the commencement of the sagittal crest. 



The lachrymals are of large size and extend upon the face 

 to such an extent that, owing partly to the width of the nasal 

 bone, they come into contact with the latter and so prevent the 

 upward process of the maxilla from reaching the nasal. This 

 feature is also met with in Phascolomys, while in some of the 

 Phalangeridse also the lachrymal extends very nearly to the nasal. 

 A very characteristic feature of marsupials is seen in the extra- 

 orbital position of the lachrymal foramen, which is single and 

 placed as in Sarcophilus. 



The nasals present two points of importance — first, the consider- 

 able expansion of their upper ends, the greatest width occurring 

 at rather more than a quarter of the length from this point ; and 

 second, the forward extension of the bones beyond the premaxillse 

 so that they overhang the nasal cavity. Their greatest length is 

 40*5 mm. and the greatest width 18"5 mm. The expansion which 

 brings the nasals into contact with the lachrymals is indeed more 

 marked than in the Phalangeridse, Dasyurus, and certain Didel- 

 phyidae in which it is characteristically present. In the forward 

 projection of the bones over the nasal cavity, the skull differs from 

 that of the Dasyuridse and agrees with those of Phalanger, 

 Trichosurus, Pseudochirus, and certain species of Didelphys ; in 

 fact the general structure and relationships of the nasal bones 

 recall most strongly that which obtains in the latter. 



The lower part of the maxillary bone is broken away at the 

 level of the infraorbital foramen, but there are two features of 

 importance. First, the upward process, as already described, is 

 completely shut off from contact with the frontal ; and second, the 

 infraorbital foramen is situated close to the suture between the 

 maxilla and premaxilla, being considerably farther away from the 

 orbit than in any existing marsupial. 



The premaxillee are of large side, approximating most in form 



