GOG On Australian Murines hitherto referred to " Mus." 



Leggadina. Mesopterygoid fossa broad in front, narrowing 

 backwards. 



Molars high, with heavy cusps, more or less resembling 

 those of Leporillus. No antero-internal secondary cingular 

 cusp on ni (except as an unusual abnormality). 

 Type. Ps. australis, Gray. 

 Other species : — 



Ps. auritus, sp. n. (see succeeding paper). 



Ps. Mgginsi, Trouess. 



Ps. lineolatus, Gould. 



Ps. murinus, Gould* (probably —australis). 



Ps. shortridgei, Thos. 



2. Thetomts, subg. n. 



Size medium. Form of skull more normal, but the 

 anterior plate of zygoma still concave in front. Palatal 

 foramina fairly long, but not widely open. Pterygoid region 

 normally murine. 



Molars fairly normal, but a distinct antero-internal cingular 

 cusp present on to 1 . Molar laminae not specially tilted up. 

 Type. Pseudomys (Thetomys) nanus (Mus vanus } Gould). 

 Other species : — 

 Ps. ferculinus, Thos. 

 Ps. gouldi, Gray. 

 Ps. gracilicauda , Gould. 

 Ps. proscoiiis, sp. n. (see succeeding paper). 



3. Leggadina, subg. n. 



Size small. Form of skull normal. Anterior zygomatic 

 plate straight or convex in front as in ordinary murines. 

 Palatal foramina narrow. Pterygoid region peculiar, the 

 parapterygoid fossse broad and very shallow, scarcely hollowed 

 at all, the ectopterygoids bordering it externally low, flat, 

 not or scarcely raised up above the level of its floor ; ento- 

 pterygoids also much lower and- less projecting than usual. 



Molars very variable, but always with a well-marked 

 antero-internal cingular cusp on ni 1 . In P. delicatulus this 

 is small, in hermannsburgensis intermediate, and in forresti 



* In my paper of 1906, " On the Generic Arrangement of the Australian 

 Eats hitherto referred to Coiiilurus, 1 ' this species, following Gould, was 

 erroneously united with " C. apicalis" in the new genus Leporillus, 

 apicalis heing chosen as the type. As a result of this mistake, the generic 

 description of Leporillus is not altogether applicable, and (an accidental 

 lapsus calami being also corrected) may run as follows : — Molars, as in 

 Notomys, without postero-internal cusps. Skull very much as in 

 Conilums. Hind feet normal, with the usual six pads. 



