Two new Jerboa-rats. 317 
From Mr. Troughton I further gather that there are no 
specimens in Sydney recognized as authentic examples of 
Sturt’s conditor, and I have therefore again had to consider 
how to deal with the Notomys skull referred to in the last 
paragraph of my 1921 paper on the genus. 
The locality of this skull was the Darling Downs, a region 
high up on the Dividing range in about latitude 28°, while 
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 600 miles from the Darling Downs, 
at a lower altitude and in a much more desert-region. 
Under these circumstances, to identify our Darling-Downs 
skull with conditor would be mere guesswork, and I therefore 
propose to describe it as new :— 
Notomys mordax, sp. n. 
Size about as in WV. gouldi, 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!. Mesopterygoid fossa fairly broad, but 
not specially broadened anteriorly, its sides practically 
parallel. Bulle rather small for the bulk of the animal, 
though slightly larger than in gould? ; conspicuously smaller 
than in the large longicaudatus. 
Teeth large and heavy. Incisors orthodont, unusually 
broad and strong, as broad but not as deep as in longicaudatus, 
flatter and less bevelled in front. 
Measurements of the type-skull :— 
Greatest length 33°5 mm.; condylo-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;. palatilar length 15; palatal 
foramina 6°8 x 2:1; breadth of mesopterygoid fossa 2-4 ; 
length of bulla 7; upper molar series 6°3. 
Hab, Darling Downs, 8. Queensland. 
Type. Adult skull. B.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. 
