316 Mr. O. Thomas on 
River, 8. Australia, which, having an incisive index of 70°-71°, 
I thought must be new if mitchelli proved to be opisthodont ; 
but, now that we know it to be orthodont, they may be fairly 
safely assigned to that species, being the only specimens 
in this country with a recorded locality. In the British 
Museum we possess one specimen, without incisors, from 
“New South Wales,” collected by Mr. Stutchbury, and 
another, of more doubtful determination, from “ Australia” 
(Gould Collection). Whether the species is now completely 
exterminated we do not know. 
The Alroy specimens would seem to demand description as 
new :— 
Notomys alexis, sp. n. 
Size of NV. mitchelli. General colour sandy brown, paler 
than in metchelli, but darker and browner than in cervinus. 
Sides paler sandy. Under surface well-defined white, the 
hairs with slaty bases except on the throat and chest, where 
they are white to the roots. Hars of medium length. Hands 
and feet quite white. Tail fairly long, well pencilled for its 
terminal third; above sandy for its proximal half, then 
blackish to the tip, below white throughout, the two colours 
well contrasted terminally. 
Skull of fairly normal shape, not with enlarged brain-case 
as in cervinus. Palatal foramina rather narrow and little 
open. Mesopterygoid fossa narrow, scarcely broadened in 
front, very different from those of cervinus in this respect, 
but agreeing with those of mztchelli. Bullee rather large. 
Incisors of all the specimens, old and young, markedly 
opisthodont, their index commonly about 51° to 56°. 
Dimensions of the type (measured in the flesh) :— 
Head and body 109 mm.; tail 135; hind foot 32; 
ear 21. 
Skull: greatest length 30; condylo-incisive length 28; 
zygomatic breadth 17; nasals 10 ; interorbital breadth 5:2 ; 
breadth of brain-case 15; palatilar length 13°3 ; palatal 
foramina 5°6X1°8; breadth of mesopterygoid fossa 1'7; 
length of bulla 6; upper molar series 5:1. 
Hab. Region of Alexandria, Northern Territory of Aus- 
tralia. Type from 35 miles 8.W. of Alroy, about 135° 40’ E. 
and 19° 30'S. Alt. 800’. 
Type. Old female. B.M. no. 6. 3.9.35. Original num- 
ber 151. Collected 29th July, 1905, by W. Stalker. Pre- 
sented by Sir W. Ingram and the Hon. John Forest. Fifteen 
specimens examined. 
