MAMMALIA. 
63 
24. MUS XANTHOPYGUS. 
Plate XXII. 
Mus xanthopygus, Waterh ., Proceedings of the Zoological Society of London for February 1887, p. 28. 
M. supra pallidb brunneus Jlavo-lavatus, ad latera jlavescens, subtus albus ; capite gris- 
cescente ; natibus fiavis ; pedibus albis ; auribus majusculis pilis, albis et flavis inter- 
mixtis obsitis ; cauda quoad longitudinem, corpus fere cequante, supra nigricante, 
subtus alba ; vellere longo et molli ; mystacibus perlongis albescentibus, ad basin 
nigris. 
Description. — Ears rather large, tail rather longer than the body, tarsi mode- 
rately long and somewhat slender : fur long and very soft : prevailing tint pale 
yellow; on the back there is a brownish hue owing to the long hairs, which 
are thickly interspersed with ordinary fur, being of that colour : in the region 
of the tail the hairs are of a rich yellow colour ; the tip of the muzzle is white, 
the feet, chin, throat and the whole under parts of the body are white ; on 
the chest and belly a faint yellowish hue is observable : the tail is well 
clothed with tolerably long hairs, those on the apical portion are the longer, 
on the upper side of the tail they are of a brown colour, and on the under 
side they are pure white : the ears are well clothed with tolerably long hairs, 
those on the inner side are of a pale yellowish colour, externally on the fore 
part they are brown, and on the hinder part they are yellowish white : the 
hairs of the moustaches are numerous and very long; some of them are white, 
but the greater portion are brownish black at the base and whitish at the 
apex : the upper incisors are yellow, and the lower are yellow-white : the 
hairs of the ordinary fur on the back are gray at the base, brownish at the 
tip, and very pale yellow near the tip : the hairs on the belly are gray at the 
base and white externally. 
In. 
Lines. 
Length from nose to root of tail 
. 5 
3 
of tail .... 
. 3 
10 
from nose to ear 
. 1 
3 
In. Lines. 
Length of tarsus (claws included) . .11 
of ear 0 7 
There are three specimens of the present species in Mr. Darwin’s collection ; 
two of them were caught when shedding their fur, and having lost the longer black 
hairs, have the upper parts of the body of a paler colour; their general tint is very 
pale, and may be described as gray, with a wash of pale yellow. 
