152 rUOCEEDINGS OF THE ACADEMY OF [Marcll, 



is so inconspicuous as to be scarcely noticeable when a specimen is 

 held at arm's length. A faint grayish patch immediately behind 

 ear. The whiskers spring from a sharply defined grayish white 

 area about 15 nmi. in diameter. A similar whitish patch, 3 mm. 

 in diameter, surrounds roots of suborbital bristles. Lateral stripe 

 huffy Avhite. As in S. humei it extends from axillary region to 

 heel and includes entire outer surface of hind leg. Under parts, 

 feet, inner surface of hind legs and entire lower portion of front 

 legs a bright brownish-red, intermediate between the chestnut and 

 rufous of Eidgway. On outer side of hind leg the red comes in 

 contact with the white lateral stripe, but on inner side it is separated 

 from the white by a line of black about 10 mm. in diameter, which 

 extends as far as heel. Shoidder and outer surface of humerus 

 orange-ochraceous, sharply defined from the black contiguous area, 

 but fading gradually through various shades of ochraceous into the 

 buffy Avhite of the lateral stripe. 



Skull and Teeth. — The skull is similar to that of Sciurus humei, 

 but the audital bullae are slightly smaller and the interpterygoid 

 space is a trifle narrower. Molars uniformly smaller than in the 

 species from the Malay Peninsula, the difference parlicidarlv 

 noticeable in the posterior lower tooth. 



Measurements. — External measurements of type: Total length, 

 505; head and body, 255; tail vertebrae, 250; hind foot, 60; hind 

 foot without claws, 58. Two other adults measure : Total length, 

 c? o:^b, 9 500 ; head and body, d" 270, 9 255 ; tail vertebra, c? 

 265, 9 245; hind foot, c? 64, 9 60; hind foot without claws, 

 cJ* 60, 9 56. 



Cranial measurements of type: Greatest length, 57 (60);' basal 

 length, 51 (53); basilar length, 48 (50); palatal length, 26 

 (26.6); length of nasals, 18.8 (19.4); interorbital breadth, 23 

 (24.4); zygomatic breadth, 34 (37); mandible, 38 (41); max- 

 illary toothrow (alveoli), 11 (11.8); mandibular toothrow 

 (alveoli), 11.4 (14). 



Specimens E.tamined. — Three, all from the type locality. 



Remarks. — This squirrel is so readily distinguishable from its 

 allies by the coloration of the cheeks that no further comparisons 

 are necessary. The three specimens show no individual variations 

 worthy of note. 



' Measurements in parentheses are those of an adult female Sciurus 

 humei from Trong, lower Siam. 



