Two neio Jerboa- rats. 317 



From j\[r. Troii;^litoii i further rather tlr.it there are no 

 specimens in Sydney recognized as authentic examples of 

 Sturt's conditor, and I have therefore af^ain had to consider 

 liow to deal with the JS'otouii/s skull referred to in the .last 

 paraf^ra|)h of my 1021 paper on the genus. 



The locality of this skull was the Darling Downs, a region 

 iiigh uj) on the Dividing range in about latitude 28°, wliile 

 the original home of conditor was near Laidey's Ponds, on the 

 Lower Darling, near its junction with the Murray, at a 

 distance of something like GOO miles from the Darling Downs, 

 at a lower altitude and in a much more dosert-region. 



Under these circumstances, to identify our Darling-Downs 

 skull with conditor would be mere guesswork, and I therefore 

 proj)osG to describe it as new : — 



Notomys mordax, sp. n. 



Size about as in N. goiddi, but the general build stouter 

 throughout. External characters unknown. Skull broad, 

 strongly built, with widely open anteorbital foramina and 

 broad frontal region. Interorbital space comparatively broad. 

 Palatal foramina long, well open, extending back past the 

 anterior root of m^. Mesoi)terygoid fossa fairly broad, but 

 not specially broadened anteriorly, its sides practically 

 parallel. Bullae rather small for the bulk of the animal, 

 though slightly larger than in gouldi ; conspicuously smaller 

 than in the large lomjicaudatus. 



Teeth large and heavy. Incisors orthodont, unusually 

 broad and strong, as broad but not as deep as iu longicaudatusy 

 flatter and less bevelled in front. 



Measurements of the type-skull : — 



Greatest length 3;5'5 mm. ; cond3do-incisive length 30 ; 

 zygomatic breadth 19*3 ; nasals 12*6; interorbital breadth 5*9 ; 

 breadth between outer corners of anteorbital foramina 9*7; 

 breadth of brain-case 16*7 ; j)alatilar length 15 ; palatal 

 foramina 6'8 X 2T ; breadth of mesopterygoid fossa 2'4 ; 

 length of bulla 7 ; upper molar series 6*3. 



Hub. Diirling Downs, S. Queensland. 



Type. Adult f^kull. 13.M. no. 46. 4. 4. 65. Gould 

 Collection. 



Readily distinguishable from all species of which the skull 

 is known by its robust build and heavy incisors. 



