146 Miller. — Seven JVew Bats collected in Simn. 



sienna present in about equal quantities. Bister soon disappearing- on 

 sides and cheel<s. Muzzle hair brown, grayish at sides. A dark shade 

 about eye. Underparts dull buff, sharply defined, much darker and 

 browner than in M. cremori center, fading to buffy gray on chin and inner 

 side of legs, down which it extends to join dull white of feet. A small 

 tawny spot on middle of chest. Fur of underparts everywhere conspicuously 

 dusky at base. 



Tai/.— Except for its shortness the tail is essentially like that of M. 

 cremoriventer. The annulation, however, is a little less distinct, and the 

 rings are more noticeably divided by cross furrows. In none of the 

 specimens is the tail perfect to extreme tip, but there is no apparent ten- 

 dency to form a pencil. 



Skull— The skull of 3Ius a»per (PI. V, Fig. 3) while of about the same 

 length as that of Mus jerdoni (PI. V, Fig. 1) ditfers conspicuously in the 

 deeper rostrum, strongly cuneate nasals, larger antorbital foramen, 

 heavier, more abruptly flaring and more depressed zygomata, and larger, 

 strongly angled supraorbital ridges. Incisive foramina short and broad, 

 their outer margins convergent anteriorly. Interpterygoid space shorter 

 and wider than in Miis jerdoni. Plate forming outer wall of antorbital 

 foramen essentially as in Mus cremoruenter, and distinctly less convex 

 above than in Mus jerdani. 



Teetli—The teeth appear to be precisely like those of Mmjerdoni. 

 Measurements. — External measurements of type: total length, 254; 

 head and body, 133; tail vertebr;e, 121; hind foot, 27 (25.5); ear from 

 meatus, 18; ear from crown, 13; width of ear, 14. An adult male from 

 the type locality: total length, 235; head and body, 121: tail vertebra', 

 114; hind foot, 28 (2(5.5). The hind foot in two specimens in alcohol 

 measures respectively, 28.6 (27.4) and 26 (25). 



Cranial measurements of type; greatest length, 34; basal length, 28; 

 basilar length, 26; palatal length, 13.4; least width of palate between 

 anterior molars, 3.6; diastema, 8.4; length of incisive foramen, 4.6: com- 

 bined breadth of incisive foramina, 2.8; length of nasals, 11; combined 

 breadth of nasals, 3.8; zygomatic breadth, 15.4; interorbital breadth, 

 5.8; mastoid breadth, 11.8; breadth of braincase above roots of zygo- 

 mata, 13.6; depth of braincase at front of basioccipital, 9.8: frontopala- 

 tal depth at posterior extremity of nasals, 8; least depth immediately 

 behind incisors, 6; maxillary toothrow (alveoli), 6; width of first upper 

 molar, 1.4; mandible, 17.2; mandibular toothrow (alveoli), 5.4. 



Hperivicns emmincd. — Six (two in alcohol), all from the type locality. 

 Remarks. — While Mas axper differs widely from the known mainland 

 representatives of the genus it is probably rather closely related to the 

 iJornean 4/"».v irhiteheadi Thomas, a species which I know by description 

 only. Mus axper •Agveeii with the Bornean animal in size, character of 

 fur, color scheme, and general aspect of skull, but ditfers from it in its 

 shorter tail, lighter color with stronger contrast between sides and belly, 

 less developed maxillary plate forming outer wall of antorbital foramen; 

 relatively wider incisive foi'amina, and apparently longer molar row, 



