NO. 1317. MAMMALS OF NORTHWEST SUMATRA— MILLER. 465 



Color. — Type: Back and sides tawny ochraceous, considerably paler 

 than that of Ridgwa}", everywhere heavily clouded })y the blackish 

 brown of the spines and longer hairs. On middle of back the dark 

 color is greatly in excess, but on sides the tawny-ochraceous .slightly 

 predominates. Crown and forehead like l)ack; cheeks clear, dull, 

 tawny-ochraceous. Outer surface of limbs tawny-ochraceous, paler 

 than that of sides, and somewhat dulled by appearance at surface of 

 slaty bases of hairs. The tawny-ochraceous completely encircles heel 

 and wrist, extending up to middle of lower leg and forearm. Under- 

 parts dull white, distinctly marked with cream buff. Throat just in 

 front of forelegs crossed b}- an ochraceous buff band about 25 mm. in 

 width. Feet dull whitish. Ears and tail blackish brown, the latter 

 indistinctly whitish beneath and at tip. 



Nine of the skins show no variation worthy of note, but the other 

 three (Nos. 114611, 11-1:612, and 114613) are so peculiar as to suggest 

 their specific distinctness. In these the tawnA'-ochraceous is absent 

 from median dorsal region, the whole of which is consequently a 

 clear slaty brown from shoulders to base of tail, strongh' contrasted 

 with color of sides. Entire ventral surface dull, light, ochraceous- 

 buft", slightly marked with whitish along median line. Otherwise as 

 in the type. As these specimens show no peculiarities other than 

 color, I think they are to be regarded as a dichromatic phase of 3fus 

 catelUfer. 



Sl'ull and teeth. — The skull and teeth are not distinguishable from 

 those of Jfus lingensis. 



Measurements. — External measurements of t3'pe: Total length, 348; 

 head and body, 202; tail vertebrae, 146; hind foot, 40 (39). Average 

 of nine specimens from type locality: Total length, 350 (309-398); 

 head and body, 195 (176-221); tail vertebrae, 155 (133-177); hind foot, 

 41 (40-43); hind foot without claws, 38.9 (37.4-41). For details see 

 table, page 466. 



Cranial measurements of type: Greatest length, 46 (47.5);'^ basal 

 length, 39 (40.4); basilar length, 37 (37.5), diastema, 13 (13.4); length 

 of incisive foramen, 7 (7); combined breadth of incisive foramina, 

 4.4 (4); length of nasals, 17 (19); greatest combined breadth of na.sals, 

 5 (5.4); zygomatic breadth, 20 (20); least interorbital breadth lo.Q (6.8); 

 mandible, 25 (25.4); maxillary tooth row (alveoli), 7 (8); mandibular 

 tooth row (alveoli), 7 (7.2). 



Specimens examined. — Thirt3^-two (2 in alcohol; 18 skulls without 



skins), all from Pulo Mansalar. 



«,^ . ^ 



« Measurements in parentheses are those of the type of Mus lingensis. 

 Proc. N. M. vol. xxvi— 02 32 



