the Australian Jerboa-rats. 539 



40 mm., the skull some 2 or 3 mm. larger than in that 

 animal. Fur rather coarser. Colour apparently similar. 

 Interorbital space coniparatively broad. Palatal foramina 

 large, open, about 2*6 mm. in breadth as compared with 1 8 

 in gouldi. Choange also markedly broader, nearly 3 mm. in 

 breadth. Orthodont ; incisive index of type 6b°. 



Dimensions of type : — 



Head and body (as originally stuffed) 118 mm. ; tail (im- 

 perfect) ; hind foot 40*5 ; ear 26. 



Skull: upper length from back of parietals 30; length of 

 nasals 12*5; interorbital breadth 6"1 ; palatdar length 14;. 

 palatal foramina 6*5 X 2'6 ; upper molar series 5*5. 



Jiab. "Interior of Western Australia, on Moore's River." 



Tt/pe. Adult skin with imperfect skull. B.M. no.44.7.9. 14, 

 the skull formerly registered as 44. 10. 15. 2. Collected by 

 John Gilbert, and received with the Gould Collection. 



This species was rightly distinguished by Gray from 

 JY. gouldi, hut never described. I use, however, the suitable 

 name he selected for it. 



It is readily distinguishable by its large and open palatal 

 foramina. 



Two specimens of it are in the Museum. One, the type, 

 has its skull comparatively perfect, the back of the brain-case 

 only being gone. In the other, a skin also received in the 

 Gould Collection, the middle portion of the skull is alone 

 present, but this is enough to show the characteristic palatal 

 foramina and choanse. 



5. Notomys mitchelli, Og. 

 Bipm mitchelli, OgUb. Trans. Linn. Soc. xviii. p. 130 (1841). 



Size comparatively small, the hind foot about 33 mm., the 

 skull about 30 ram. in total length. Colour fawn above, 

 whitish below. Tail long, pencilled, bicolor. 



Skull of average Murine proportions. Palatal foramina 

 rather small. Choanae not specially widened. Bullse rather 

 large. Incisors markedly opisthodont, the incisive index 

 about 54°. 



Hab. Interior of Australia, ranging over a wide area from 

 the Northern Tenitory (Alroy), through Central Australia 

 (Kdlalpanima, Lake Eyre), to Western New South Wales. 

 Type-locality Reedy Plains, near the junction of the Murray 

 and Murrumbidgee. 



Tt/pe in the Sydney Museum. 



The common species over the greater part of Central and 

 Northern Australia. Distinguished by its opisthodont incisors 

 and narrow choana?. 



