564 FOSSIL MARSUPIAL WITH LARGE GROOVED PREMOLARS, 



Most of the marsupials belong either to extinct species or to 

 species not now living in the district. 



The subject of the present paper is one of the most interesting 

 forms found, and as I am not aware of its having been previously 

 observed, and as its dentition is unlike that of any known mar- 

 supial, I have formed a new genus for it, called after the abori- 

 ginal name of the district. 



Burr AM Ys parvus, gen. et sp. nov. 



The form is characterised by having above and below a. large 

 grooved premolar followed by three well developed molars. In the 

 lower jaw the large premolar has six well marked grooves on each 

 side passing upwards and slightly backward and giving the tooth a 

 serrated edge. As the grooves run approximately parallel to the 

 anterior border of the tooth and to each other, and as the anterior 

 and posterior borders converge considerably above, there is left a 

 considerable portion of the posterior part of the tooth ungrooved. 

 This premolar is placed obliquely in the jaw, the line of its edge 

 passing considerably outwards from the line of the molars. The 

 first molar bears some resemblance to the corresponding tooth in 

 Petaurus, having two posterior and a large anterior cusp: it differs, 

 however, in the anterior cusp pointing more outwards. The second 

 molar is slightly oblong and has four well developed cusps; of these 

 the anterior outer cusp has a small secondary one springing from it, 

 while the posterior inner one is partly divided by a well marked 

 furrow. The third molar is less developed and apparently quadri- 

 tubercular. Behind this there appears to be a rudimentary single 

 rooted and apparently functionless fourth molar, which is generally 

 lost in the specimens found. In front there is a long straight 

 flattened and pointed incisor directed considerably upwards from 

 the axis of the jaw. Between the base of this incisor and the 

 anterior part of the large premolar are five minute tooth sockets 

 which have apparently been occupied by tAvo double-rooted pre- 

 molars and a single-rooted anterior tooth — possil^l}^ a minute 

 second incisor. Behind, the jaw has a very marked inflected angle 



