N0.12G9. ANDAMAN AND NICOBAR MAMMALS— MILLER. 771 
Sj^ecimens examined. — One, the type. 
Remarks. — Although represented by onlj^ one spec-imen the rat of 
isolated Car Nicobar is evidently distinct from those of the larger 
southern islands. That its small size is not due to immaturit}^ is shown 
by the fact that the tA^pe is fully adidt, with distinctly worn teeth, a 
much older individual than several of the specimens of Mus hurrus. 
MUS BURRESCENS, new species. 
Type.—M\x\i female (skin and skull). No. 111789, U.8.N.M. Col- 
lected on Great Nicobar Island March 12, 1901, by Dr. W. L. Abbott. 
Original number, 926. 
Characters. — Externally similar to 3fas harms., but red of upper 
parts a little more intense. Skull distinguishable from that of the 
related species by the form of the nasal bones, which are strongl}^ con- 
tracted a little in front of middle. 
Color. — The upper parts are slightly more red than in 2j[us harms 
and the grizzle produced by the black hair-tips is less coarse, differences 
easily appreciable on comparison. Otherwise the two animals are 
entirely similar so far as external characters are concerned. 
Skull. — The skull is like that of Mus hurrus except in the form of 
the nasal bones. The outer margin of each nasal, straight or nearly 
so in J/us hurrus, is here abruptly concave at middle. The result is a 
spatulate outline of the two nasals together, quite different from the 
regular cuneate form characteristic of Mus hurrus and 3fus hurrulus. 
Teeth. — Teeth as in 3£us hurrus. 
Measurements. — External measurements of type: Total length, 108 
mm,; head and body, 206; tail, 202; hind foot, 40 (38); ear from mea- 
tus, 21; ear from crown, 16; width of ear, 15. 
Cranial measurements of type: Greatest length, 11.6 mm.; basal 
length, 10; basilar length, 38; length of nasals, 16; combined breadth 
of nasals, 5.6; zygomatic breadth, 21.8; interorbital constriction, 6.8; 
maxillary toothrow (alveoli), 7.1. 
Sjjecimens examined. — Two, both from Great Nicobar Island. A 
specimen from Little Nicobar may represent this species, but it is too 
young for positive determination. 
Remarks. — The cranial character b}^ which this species is distin- 
guished from its allies though trivial is apparently of perfect con- 
stanc}'. In none of the twelve skulls of Mus hurrus is there any 
approach to the spatulate form of nasals. 
