Type.—Adult male (skin and skull) No. 104712 U. S. National Museum. Collected on Sirhassen Island, South Natunas, June 5, 1900. Original number 442.
Characters.—In general similar to Bornean specimens of Tupaia tana, but smaller (hind foot 47 instead of 52, greatest length of skull 55 instead of 60), gray markings on head and shoulders less distinct, and red of tail brighter. Rostral portion of skull less attenuate than in Tupaia tana.
Color.—The color so exactly resembles that of the common Bornean Tupaia tana as to need no detailed description. Gray of head darker than in the Bornean animal and light shoulder markings less distinct and sharply defined. Under side of tail light orange-rufous, darkening to ferruginous toward edge. (In T. tana these colors are replaced by dull ferruginous and hazel respectively.)
Skull and teeth.—The skull is throughout much smaller than in specimens of Tupaia tana from Borneo. In form it differs from that of T. tana in less slender and elongate rostrum, narrower braincase and slightly shorter audital bullæ. Suborbital vacuity much broader than in T. tana. Teeth as in the Bornean animal.
Measurements.—External measurements of type: Total length 355; head and body 203; tail vertebræ 152; hind foot 46.4 (44). Average and extremes of four adults from the type locality: total length 367 (365-371); head and body 203; tail vertebræ 163 (162-168); hind foot 45.4 (44-46.6); hind foot without claws 42.5 (41-44).
Cranial measurements of type: greatest length 54.6 (61);[25] basal length 49 (54); basilar length 46.4 (51); median palatal length 48 (53); distance from lachrymal notch to tip of premaxillary 27.6 (31); least interorbital breadth 14.4 (16); zygomatic breadth 25 (28.4); mandible 38 (41); maxillary toothrow (behind diastema) 20 (21.4); mandibular toothrow (behind diastema) 17 (18).
Specimens examined.—Five, all from the type locality.
GALEOPITHECUS VOLANS (Linnæus).
1894. Galeopithecus volans Thomas and Hartert, Novitates Zoologicæ, I, p. 657. September, 1894 (Bunguran and Sirhassen).
Two specimens from Sirhassen and two (one young in alcohol), from Bunguran. Also fœtus of one of the Sirhassen specimens.