SCIURUS PROCERUS sp. nov.
1894. Sciurus tenuis Thomas and Hartert, Novitates Zoologicæ, I, p. 659. September, 1894 (Bunguran).
1895. Sciurus tenuis Thomas and Hartert, Novitates Zoologicæ, II, p. 492. December, 1895 (Bunguran).
Type.—Adult male (skin and skull) No. 104698 U. S. National Museum. Collected on Bunguran Island, North Natunas, July 18, 1900. Original number 574.
Characters.—Externally similar to Sciurus tenuis though somewhat smaller. Skull very much smaller and relatively broader than in the related species.
Color.—The color is exactly like that of Sciurus tenuis from Singapore.
Skull and teeth.—Except that it appears to be broader throughout, relatively to its length, the skull of Sciurus procerus is essentially a miniature of that of S. tenuis, as the braincase shows none of the tendency to increased depth characteristic of the Bornean animal. Ratio of rostral depth to distance between middle of interparietal and lower rim of audital bulla, 50. This ratio is 49 in S. tenuis.
Measurements.—External measurements of type: total length 235; head and body 140; tail vertebræ 95; hind foot 35 (33). Average and extremes of four specimens from the type locality: total length 239.5 (235-247); head and body 140; tail vertebræ 99.5 (95-107); hind foot 35.2 (34-36.5); hind foot without claws 32.9 (31.8-34).
Cranial measurements of type: greatest length 34 (38);[17] basal length 28.6 (32); basilar length 26 (29); palatal length 14.6 (16); diastema, 7.6 (8.8); length of nasals 10.4 (11.4); greatest breadth of nasals 4.8 (5.6); interorbital breadth 12 (12.6); zygomatic breadth 20.8 (21); greatest breadth of braincase 17 (17.6); cranial depth from middle of interparietal to lower rim of audital bulla 14 (15); least depth of rostrum 7 (7.2); mandible, 20 (21); maxillary toothrow (alveoli) 6 (7); mandibular toothrow (alveoli), 6 (7).
Specimens examined.—Six, all from the type locality.
Remarks.—This species is immediately distinguishable from its allies by its small skull, scarcely larger than that of Funambulus macclellandi.