104 MUS. 
Note.— This, the typical genus of the Family (RoDENT1A) is,” 
Mr. Oldfield Thomas writes, ‘by far the largest of the Order, 
and indeed of the whole Class MamMA.ia, containing not less 
than one hundred and twenty species spread over the whole of 
the Old World with the exception of Madagascar. The number 
of species is, on the whole, much more considerable in tropical 
than in temperate regions, while but few are found where the 
climate is excessively cold.” The following paragraph from the 
same pen is of more than ordinary interest, and to it we would 
call the attention of our northern zoologists, whose opportunities 
of examining the animals at different seasons and different 
altitudes so far exceeds ours. ‘It is an interesting fact in 
connection with climate that many of the species living in hot 
countries have their fur more or less mixed with flattened spines, 
and that these spines appear to be shed during the winter and to 
be replaced by hairs, the latter naturally affording a warmer 
covering for the animal than the former.” 
1. Mus ruscipes, Waterh. (1840). 
Dusky-footed Rat. 
Form stout ; ears moderate ; tail equal in length to the body ; 
tarsi moderate ; fur very long. General color above blackish- 
brown with an admixture of gray ; below grayish-white. Feet 
brown: tail black, sparingly covered with short bristly hairs. 
Incisors orange. 
Dimensions.--Head and body to six and a half inches ; tail to 
four and a quarter inches. 
Habitat.—The entire southern half of Australia ; Tasmania ; 
Islands of Bass’ Strait. 
References.— Waterhouse, Voy. Beagle, Mamm. p. 66, pl. xxv. ; 
Gould, Mamm. Austr. iii. pl. i1. 
Note.—This Rat is partial to the neighborhood of water, 
frequenting the banks of streams and lagunes, swampy localities 
among long grass and dense brush, and swims with great ease 
and rapidity. 
2. Mus VELLEROSUS, Gray (1847). 
Tawny Rat. 
Form stout ; ears moderate ; tail shorter than the body ; fur 
very long, close, and rather soft. General color above reddish- 
brown with interspersed whitish hairs; below paler. Feet, and 
tail brown, the latter with a few short bristly hairs. Incisors 
yellow. 
