760 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiv. 
guished from the terete hairs. The bristles are numerous on middle 
of Imck and on sides, but are practically absent from rump and from 
region in front of shoulders. The back is rather plentifully sprinkled 
with coarse terete hairs about 50 nnu. in length, but these are not 
sufficiently numerous to influence the general appearance of the fur. 
Whiskers coarse, the longest 70 mm. in length. Supraorbital bristle 
about 10 mm. less. 
Colo?'. — Back a coarse grizzle of ])lack and dull ochraceous ])uft' (dis- 
tinctly darker than Ridgway's PI. v, lig. 10) the latter element in 
excess. The efl'ect is similar to the general color of Mus validm but 
considerably more yellow. The longer hairs are strongly lustrous, so 
that in certain lights the fur has a noticeable steely gloss. This sheen 
is very conspicuous at sides of shouklers when the skin is viewed from 
in front. Sides like back but with buff even more predominant. 
Underparts and inner surface of llml)s nearly uniform mouse gray 
(paler than that of llidgway). This color is due to the combined effect 
of the drab underf ur and whitish hair tips. It extends entirely around 
upper lip and spreads over cheeks, where, however, it becomes mixed 
with ochraceous buff'. Eye surrounded by a very faintly indicated 
dark ring. Whiskers black. Ears and tail uniform dull dark brown 
throughout. Feet sprinkled w^ith line whitish hairs, these nowhere 
abundant enough to conceal the light brown skin. 
Tail. — The tail is rather inconspicuously annulated — that is, the 
boundaries of the scales are less sharply defined than in most rats of 
the same size. At middle there are about 10 rings to the centimetei'. 
At first sight the tail appears to be naked, Imt on close inspection it is 
seen to be beset with tine appressed hairs 1 to 2 mm. in length, two or 
three of which spring from the base of each scale. 
MammcB. — In the single adult female collected one pectoral and three 
inguinal mammti? are plainly visible on each side. The skin is in bad 
condition in the region which the anterior pair of pectoral mamm^ 
would occupy if present. On the label Dr. Abbott has written 
"mamma? apparentl}' ten." 
Feet. — The feet show no peculiarities of form or structure. Soles 
naked, with six well-developed tubercles. 
Earf<. — The ears are moderately large, their height from crown 
exactly equal to distance between eye and tip of muzzle. In form 
they are not peculiar. Both surfaces are naked except for a fine, close 
pubescence. 
Shill. — The skull of Mus stoicus differs conspicuously from that of 
Mus validus, Mus vociferans, or Mus howersi in its much lighter 
structure and more slender form. Viewed from above it does not 
differ widely from the skull of Mus vociferans, except that it is more 
narrow throughout, a difference more noticeable in rostrum and brain - 
case than in the zygomatic region. Supraorbital ridges about as in 
Mus vociferans. The plate of the maxillary forming outer wall of 
