RATUFA SIRHASSENENSIS (Bonhote).
1894. Sciurus bicolor albiceps Thomas and Hartert, Novitates Zoologicæ, I, p. 659. September, 1894 (Sirhassen).
1900. Ratufa ephippium sirhassenensis Bonhote, Ann. and Mag. Nat. Hist., 7th ser., V, p. 498. June, 1900 (Sirhassen).
Two specimens, Sirhassen, June 8, 1900.
This species, though related to Ratufa ephippium, with which it agrees in color-scheme, is sharply differentiated by its small size and cranial peculiarities. It is in no way closely allied to Ratufa bunguranensis and R. nanogigas.
As compared with that of Ratufa ephippium sandakanensis Bonhote, the skull in addition to its small size (greatest length 57 instead of 65) differs in general narrowness, in the relatively greater breadth of the nasal branches of the premaxillaries, and in the form of the audital bullæ. When the skull is held upside down and viewed from behind the bullæ are seen to be narrower than in the Bornean animal and to rise to a much greater height above the surface of the basi-occipital.