NO. 1269. AXDAMAX ASn XICOBAR MAMMALS— MILLER. 767 
Teeth. — The teeth of the type are somewhat worn, but the}" appear 
to be in every wa}- similar to those of 3fus rattus. 
Mea8nre)iienU. — External measurements of type: Total length, 387 
mm.; head and body, 202; tail, 185; hind foot, 35 (33); ear from 
meatus, 19; ear from crown, 1-1; width of ear, 15. 
Cranial measurements of type: Greatest length, 44 mm,; basal 
length, 40; basilar length, 38; palatal length, 22.6; least width of 
palate between anterior molars, 4.6; diastema, 12.6; length of incisive 
foramen, 7.8; combined breadth of incisive foramina, 4; length of 
nasals, 16; combined breadth of nasals, 4.6; zygomatic breadth, 21.8; 
interorbital breadth, 6.4; breadth of braincase above roots of zyg-o- 
mata, 16.2; mastoid lireadth, 16,8; occipital depth at front of ])asioc- 
cipital, 13; frontopalatal depth at posterior extremity of nasals, 9.6; 
least depth of rostrum immediately behind incisors, 7.6; mandible, 25; 
maxillary toothrow (alveoli), 7.8; width of front upper molar, 2; 
mandibular toothrow (alveoli), 6.8. 
Specimens examined. — One, the type. 
RemarJiS. — Mus pidliventer differs so conspicuously from its allies 
of the Mus rattus group that it needs no special comparison with any 
of them. The flattened skull and dark color of the under parts are 
sharply diagnostic. 
MUS ATRATUS, new species. 
Ti/jx.—A^nM female (skin and skull), U.S.N.M. No. 111868, Col- 
lected on Barren Island, Andamans, January 7, 1901, })y Dr. W. L. 
Abbott, Original number, 818. 
Chaixictei's. — Size and proportions as in Mus andamanetisis., but 
fur spineless. Color of under parts yellowish brown, back strongly 
suffused with black (often entirely black). Skull shorter, broader, 
and more robust than that of Mus andamanensis.^ the audital bullae 
smaller. Teeth as in Mus andamanensls and Mus rattus., but much 
larger. 
Fur. — The fur consists of the usual elements. The spines, however, 
are so reduced in diameter as to appear like ordinary hairs unless 
examined with a lens. 
Color. — Upperparts almost exactly as in Mus flehlUs and Mus 
andamanensis, except that the fur is strongly suffused with a slaty 
black like that of Mas rattus. In two of the eight specimens the 
brown remains in excess of the black, but in the others (including the 
t^'pe) the latter predominates, nearly or quite to the exclusion of the 
brown. Belly 3^ellowish brown (rather paler and less yellow than the 
ochraceous Iniff' of Ridgwa}") in the brown-backed specimens, slaty in 
the others. Only one skin, however, lacks a distinct brownish wash 
over the slat}^ under parts. Feet sprinkled with whitish or slaty hairs. 
Ears and tail uniform dark brown. 
