SCIURUS RUTILIVENTRIS sp. nov.
Type.—Adult male (skin and skull) No. 104658 U. S. National Museum. Collected on Pulo Midei (Low Island), South Natuna Islands, May 24, 1900. Original number 405.
Characters.—Size slightly greater than that of Sciurus lutescens and S. seraiæ, but not equal to that of the Bornean or Bunguran representatives of S. notatus. Color above as in S. seraiæ. Under parts bright clear orange-rufous.
Color.—Color exactly as in Sciurus seraiæ except that the pale side stripe is light cream-buff and the under parts are bright orange rufous. Tail without trace of red suffusion.
Skull and teeth.—The skull and teeth are a trifle larger than in Sciurus lutescens and S. seraiæ, but the difference is scarcely a tangible one.
Measurements.—External measurements of type: Total length 368; head and body 190; tail vertebræ 178; hind foot 45 (41). Average and extremes of seven specimens from the type locality: total length 356 (330-368); head and body 186 (178-190); tail vertebræ 173 (165-184); hind foot 45.5 (43-48); hind foot without claws 42.2 (39.5-45).
Specimens examined.—Seven, all from the type locality.
Remarks.—This squirrel is remarkable among the Natuna members of the S. notatus group for the brilliant color of its under parts. In this respect it surpasses all of the related forms with which I am acquainted. The red color is, however, strictly confined to the body, showing no tendency to spread to the tail as in S. miniatus of the Malay Peninsula.