406 
HORN EXPEDITION—MURIDS. 
Skull. 
B? 
C? 
Greatest length 
- 
230 
22-6 
Basal length 
- 
19-3 
19-5 
Greatest breadth 
- 
12-5 
12-0 
Nasals, length 
- 
7-4 
7-2 
Nasals, greatest breadth 
- 
2-3 
2*5 
Interorbital breadth 
- 
3-5 
3-4 
Interparietal length 
3'2 
3-2 
Interparietal breadth 
- 
8-1 
8-2 
Brain-case, breadth 
- 
11'2 
11-0 
Anterior zygoma root 
- 
2-4 
2-4 
Diastema . . - 
- 
5-7 
5-8 
Palate, length 
- 
13-0 
130 
Anterior palatina foramina 
- 
4*5 
4-2 
Uj)pper molars, length 
- 
3-2 
3-8 
Lower molars, length 
- 
3-1 
3*5 
Condyle to incisor tip 
- 
14-0 
14-2 
Coronoid tiji to angle 
- 
5’4 
5-3 
Habitat .—George Gill Range, Hermannsburg, and Cliarlobte Waters, Central 
Australia, February, 1895. 
Mastacomys, sp. Fig. 6, d—f. 
Four immature examples are referred to this genus, and are of interest as 
being the lirst living representatives obtained on the Australian continent. In 
1882* Mr. Oldlield Thomas formed the genus to receive a mouse from Tasmania 
which he named Mastacomys fuscus, and fossil fragments obtained in the Wellington 
Caves, New South Wales, have been referred to this species, f The specimens 
Ann. Mali-. Nat. Hist. (5), i.\., }). 413, 1S82. 
t Brit. Mus. Cat., Fossil Rlaninialia, i., p. 227, 1885. 
