74 
MURIDAE RECORDED FROM VICTORIA 
to the whole. Sides of body lighter with fewer long hairs, grading into 
greyish-white of ventral surface. Ventral fur slaty for three-fifths of length, 
tipped with soiled white, the grey showing through. Head as body ; lighter 
on cheeks and muzzle, upper lip greyish-white. Mysticial vibrissae long 
(39 mm.), shorter hairs white, longer hairs black at base with white tips. 
Ears long; purplish-grey in freshly-killed animal; sparsely clothed with white 
and grey adpressed hair. Tail longer than head and body; greyish-brown 
above, white on sides and below; well clothed with hair 3-4 scales in length 
which, nevertheless, does not hide scales. Manus and pes white; well 
clothed with silvery-white adpressed hair which forms a fringe around the 
nails. 
Skull. — Smooth and rounded with a long narrow muzzle. Anterior edge of 
zygomatic plate slightly concave and sloping gently forward to its base. 
Bullae small, anterior-posterior length about half that of diastema. 
Teeth. — Comparatively large and heavy. Laminae not tilted; no anterio- 
internal cingular cusp on M 1 . 
Dimensions of Skin (from flesh). — Head and body, 115 mm.; tail, 134 
mm. ; hind foot, 29 mm. ; ear, 22 mm. 
Dimensions of Skull. — Greatest length, 32 mm. ; basal length, 27 mm. ; 
greatest breadth, 16 mm. ; nasals, 11 8 X 4 mm. ; interorbital breadth, 5 mm. ; 
palate length. 15 8 mm.; breadth inside M 2 , 3 4 mm.; breadth outside M 2 , 
7 mm. ; palatal foramina, 6 mm. ; diastema, 8 mm. ; upper molars, 5 • 5 mm. 
Type Locality. — Otway Forest, Victoria. 
No details of the habits of this mouse have been discovered. 
It inhabits dense, scrubby forest country, which also harbours 
a large population of Rattus assimilis. It is a south-eastern 
representative of the albocinereus-glaucus group. 
Pseudomys (Gyomys) desertor Troughton. 
Mastacomys sp. Waite (nec. Thomas), Rept. Horn Expdn., ii, p. 406, 
pi. xxvi, 1896; id. Proc. Roy. Soc. Viet., x, 2, p. 128, 1898. 
Mus nanus Waite (nec. Gould), Proc. Rov. Soc. Viet., x, 2, p. 128, 
pi. vi, 1898. 
Pseudomys (Thetamys) nanus Wood Jones, Mamm. Sth. Aust., iii, 
p. 314, 1925. 
Pseudomys ( Gyomys ) desertor Troughton, Rec. Aust. Mus., xviii, 
p. 293, 1932. 
The Desert Mouse was for many years confused with the 
Little Mouse, Pseudomys (Thetomys) nanus Gould, 1858, 
which it outwardly resembles very closely. In 1932 Trough- 
ton (loc. cit.) found that it had no cingular cusp on M 1 , and 
placed it in the subgenus Gyomys as a new species. 
Size small. General colour about tawny-olive, heavily pencilled with dark- 
brown hairs. Dorsal fur moderately long (11 mm.) and crisp; slate for 
more than half its length, tipped with cinnamon-buff. Long hairs numerous, 
deep brown. Sides of body lighter, grading into brownish-buff of ventral 
surface. Ventral fur basally grey, tipped with brownish-white, the grey 
showing through. Head as body ; cheeks and muzzle a little lighter. Mysticial 
