As Mr. Thomas has pointed out to me, after examining a specimen of the latter, Ratufa bunguranensis is closely allied to R. pyrsonota. Indeed its relationship to the Siamese species is much closer than to the R. ephippium of Borneo. Together with R. pyrsonota the Bunguran giant squirrel differs conspicuously from that of Borneo in its narrow skull, lengthened audital bullæ, dark feet, dark median line on under surface of tail, and entirely brown back. From R. pyrsonota, however, it is readily separable by its darker, less ochraceous color both above and below, drab washed back, and by the much less distinct annulation of the hairs of the dorsal surface.
RATUFA NANOGIGAS (Thomas and Hartert).
1895. Sciurus bicolor nanogigas Thomas and Hartert, Novitates Zoologicæ, II, p. 491. December, 1895 (Pulo Laut).
1900. Ratufa ephippium nanogigas Bonhote, Ann. and Mag. Nat. Hist., 7th ser., V, p. 498. June, 1900 (Pulo Laut).
Four specimens, all from Pulo Laut, the type locality.
This strongly characterized dwarf species is allied to Ratufa pyrsonota and R. bunguranensis with which it agrees in color scheme. It is in no way closely related to the large Bornean R. ephippium.
RATUFA ANGUSTICEPS sp. nov.
Type.—Adult male (skin and skull) No. 104646 U. S. National Museum. Collected on Pulo Lingung, off south coast of Bunguran, June 17, 1900. Original number 481.
Characters.—Externally like Ratufa anambæ and R. melanopepla. Skull about equal to that of latter in length, but conspicuously narrower.
Color.—As the color is precisely like that of Ratufa anambæ and R. melanopepla it requires no description.
Skull and teeth.—The skull is immediately recognizable by its general narrowness, but particularly in the region of the anterior zygomatic roots. Ratio of lachrymal breadth to greatest length, 39. In the other black backed species it is about 42. Audital bullæ narrower and more elongate than in R. melanopepla, and more elevated above level of basi-occipital (when skull is held upside down). Lateral processes of basi-occipital obsolete.