110 MUS. 
Note.—Dr. Ramsay is undecided as to whether this species 
should be placed in the genus Mus or in Hapalotis (Conilurus 
of this work). 
18. Mus arcurus, Zhomas (1889). 
White-tailed Rat. 
Tail rather longer than the head and body. Ears rounded, 
reaching just beyond the middle of the eye when laid forward. 
General color above pale sandy-rufous, the hairs slate-colored 
basally ; muzzle and underside of body white, the hairs of the 
chest and belly rufous basally ; hands and feet pure white ; tail 
wholly white, more thickly clothed than usual, the tip slightly 
pencilled. 
Dimensions.—Head and body to three and a third inches; tail 
to four inches. 
Habitat.—South Australia. 
Reference.—Thomas, Ann. Nat. Hist. (6) ili. 1889, p. 433, fig. 
p. 434 (upper molar teeth ). 
Note.—As in the case of Dr. Ramsay’s species just described, 
Mr. Thomas was undecided as to the exact position to which to 
assign this curious form; he remarks: “ Mus argurus has the 
external characters and the skull of JMZ/us, with the molars of 
Hapalotis ; and I am somewhat in doubt as to which of the two 
it should be put into. It seems indeed probable that the charac- 
ters of these two genera will be found so to blend together in the 
different species as to necessitate their ultimate union, notwith- 
standing the very striking characters presented by the more 
typical species of Hapalotis.” 
The following eight forms of Jfws, which have been described 
by Messrs. Higgins & Petterd from Tasmania, are here introduced 
for the sake of comparison with southern continental species, as 
it is impossible for the writer with the data to hand to form an 
opinion as to their validity or otherwise. It is not, however, at 
all probable that the small island of Tasmania should possess no 
less than eleven indigenous species of Jus, while but seventeen 
have been described from Australia, one only being common to 
both islands. 
19. Mus eriseocaRuLeEvs, H. & P. (1882). 
Blue Rat. 
Ears naked and moderately long ; tail shorter than the head 
and body, sparsely clothed; fur long. General color above 
bluish-gray, sides and below ashy-gray ; feet clothed with short 
yellow hairs, tail with short stiff black hairs, 
