NO. 1317. 



MAMMALS OF NORTHWEST SUMATRA— MILLER. 



457 



close inspection. The l)laok of cheeks extends und(>r chin across an 

 area about 10 mm. in width. On front legs the red area is much wider 

 than the black, and on inner side it extends to naked surface of palm. 

 In S. j}/uto the l)iack area is the more extensive, and it encircles the 

 wrist just above pahii. On hind legs the same ditlercnces occur. The 

 red area is much wider in the Sumatran than in the Bornean form, 

 and it usually extends to edge of naked sole, though occasionally the 

 black narrowly encircles ankle. 



Skull and teeth. — The skull and teeth so closely resemble those of 

 Sciurus jyluto that I can detect no tangible differences. 



Measureiiient.^. — External measurements of type: Total length, 485; 

 head and body, 260; tail vertebrae, 225; hind foot, 58 (53). Average 

 of twelve adults from the type locality: Total length, 473 (430-1:98); 

 head and body, 247 (230-263); tail vertebra?, 227 (200-240); hind foot, 

 58.1 (57-59); hind foot without claws, 53 (51-55). For details, see 

 table, page 457. 



Cranial measurements of tj'pe: Greatest length, 58 (56);^* basal 

 length, 50 (49); basilar length, 46.6 (46); diastema, 13.6 (13.6); length 

 of nasals, 17.8 (16.6); greatest breadth of both ntisals together, 8.8 

 (8.6); least interorbital breadth, 23 (22.6); zygomatic breadth, 34.6 

 (34); mandible, 37 (37); maxillary toothrow (alveoli), 11 (11); man- 

 dibular toothrow (alveoli), 11 (11.4). 



Sjjecliiiens exaiiiined. — Twelve, all from Tapanuli Bay. 



Remarks. — While Scinrus erehus rather closel}^ resembles S. pluto, it 

 is readily distinguishable from the Bornean animal by its greater size 

 and by the absence of the pale lateral stripe. There is not the slightest 

 indication of this stripe in any of the twelve skins, while in each of five 

 specimens of Scinrus j)lut(> it nia}^ be easily traced. The difference in 

 extent of the red on the lesfs is a less constant character. 



Measurements of Sciurus erehus. 



a Type. 



" Measurements in parentheses are those of an adult male Sciurm pluto from British 

 North Borneo (No. 34941). 



