NO. 12G9. ANDAMAN AND NICOBAR MAMMALS— MILLER. 769 
Characters. — Size and general appearance much as in Musp%illiventei\ 
but tail shorter, back less distinctl}^ grizzled, and belly light buff. 
Fur spineless. Mammse 10. Skull nuich like that of Mus norvegicus. 
Fur. — The fur is like that of Mxis atratus^ that is, the spines are so 
reduced in diameter that on casual examination they do not appear 
different from the surrounding hairs. They are, however, slightly 
larger than in 3£us atratus. 
Color. — Back and sides a fine grizzle of black and russet, the colors 
nearly as in Mus pull wenter., but grizzle less distinct. The two ele- 
ments are in about equal parts on back, but on sides the russet is con- 
siderably in excess of the black, and at the same time slightly obscured 
by the drab gray of the underfur. Under parts and inner side of legs 
cream-buff* to base of hairs. Crown and forehead like back, but a lit- 
tle tinged with gray; cheeks washed with drab. Feet scantily clothed 
with whitish and brownish hairs. Ears and tail uniform dark brown. 
Tall. — The tail is coarsely and distinctly annulated. At middle 
there are about eight rings to the centimeter. To each scale there are 
from one to three stiff' hairs varying in length from 1 to li millimeters. 
Manuiue. — There are ten mammte, four pectoral and six inguinal. 
Feet. — The feet are in no way peculiar. Soles naked, with the 
usual six tubercles. 
Far's. — Ears as in the related species. 
Skull. — In a general way the skull of Mus hurrus rather closely 
resembles that of Mus norvegicus. It is slightly smaller than that of 
the house rat, however, the dorsal profile is less convex, the rostrum 
shorter and broader, the interorbital region less constricted, the zygo- 
matic arches less liaring, the braincasc broader and less elevated, the 
inter pterygoid space wider, and the audital bullfe slightly different 
in form and more resembling those of Jhis rattus. Nasal bones grad- 
ually narrowed from front to back, their outer margins nearly straight 
except for the usual slight downward curve. Posterior portion of 
mandible somewhat deeper than in Mus norvegicus. 
Teeth. — The teeth are relatively somewhat larger than in the house 
rat, but the enamel pattern shows no peculiarities. 
Measurements. — External measurements of type: Total length, 430 
mm.; head and body, 215; tail, 215; hind foot, -13 (41); ear from 
meatus, 24; ear from crown, 18; width of ear, 17. Average of ten 
specimens from the tvpe localit}': Total length, 407 (385-430); head 
and body, 205 (195-225); tail vertebra?, 202 (193-215); hmd foot, 42.5 
(42-43); hind foot, without claws, 40.6 (40-41.4). For detailed meas- 
urements, see table, page 772. 
Cranial measurements of type: Greatest length, 47.6 mm. (49)'; basal 
length, 43 (43.6); basilar length, 40 (41); palatal length, 23.4 (23); least 
width of palate between anterior molars, 5.4 (5); diastema, 14 (14); 
^Measurements in parenthesis are those of an adult female J/ws nonegicus. 
Pioc. N. M. vol. xxiv— 01 49 
