THE RAT-KANGAROOS, 
65 
| Characters.—Size medium ; nak 
_ backwards along the top of the 
hind feet long, short-haired. 
ed portion of nose extending 
muzzle ; face long and narrow ; 
Fur and general coloration as 
in last species ; tail grey at base, deepening to black at tip. 
Length of head and body about 15} inches 3 Of tail 7 inches, 
| Distribution.—South-western Australia. 
| HI, COMMON RAT-KANGAROO. 
Didelphis tridactyla, Kerr, 
Bp (2792,) 
_ Didelphis murina, Cuvier, Table Element., p. 126 (1798). 
| Aypsiprymnus murinus, Goldfuss, Handb. Zool., 
POTOROUS TRIDACTYLUS. 
Linn. Anim, Kingdom, p. 198 
P- 447 
(1820). 
| Hypsiprymnus apicalis, Gould, Mamm. Austral., pl. Lxviii. 
(1851). 
| Potorous rufus, Higgins and Petterd, Proc. Roy. DoG.,.. lass 
mania, 1883, p. 181, 
' Potorous tridactylus, Thomas, Cat. Marsup. Brit. Mus., 
(1838). 
| (Plate VIIL) 
Pp: 127 
Characters.—Size variable, large or medium ; other external 
icharacters as in P. Silvertt, but the naked portion of the nose 
extending rather further upwards on the muzzle. Length of 
‘head and body reaching to 163 inches ; of tail 9 inches, 
Distribution—New South Wales, Victoria, South Australia, 
and Tasmania. 
——— 
Varieties.—One Tasmanian race (P. apicalis) attains larger 
dimensions than specimens from the mainland, and also has 
the fourth premolar tooth larger and with four instead of three 
grooves. There is also a dwarf Tasmanian form (P. rufus) in- 
lerior in size to mainland examples ; but intermediate varieties 
‘-Pp€ar to connect all three together. 
F 
