PTEROMYS LEPIDUS. 
Ord. IV?* Rongeurs, Carter* W Division. 
Oed. IV. Glires, Linn. Syst. 
Ord. -IV; Prensiculantia, IUiger. Fam. 9, Agilia. 
PTEROMYS, Cuv. Geoff'r. IUig. 
Sciurus, Linn. Briss. Schreb. Pal/as, §c. 
Petauristus, G. Fischer, Zoognosia, VoL III. 7* 498* 
Char. Gen. — Dentium formula ; ' Primores -§-, Molares £i Primores superiores 
pagina antica hevigati, infcriores compressu Pro Laniariis diastema. Molares 
abrupti obducti tritores, supra antico acccssorio. 
Rostrum obtusiusculum. Labrum fissurru Sacculi buccales nulli. Auricula? rotun- 
datse. Cauda elongata. Mamma? apertie, pectorales et ventrales. 
Pedes dermopteri : patagium lumbare sa?pius in angidnni anteriorcm dilatatum osse 
fultum, interdum patagium collare adest. Antipodes digitis quatuor et verruca 
hallucari, scelides pentadactyla\ IUiger. 
Pteroniys nigricante-fuscus, subtus albus, capite dorsoque medio canescentibus, 
cauda corpore longiore oblonga plana disticha, auriculis oblongis simplicibus 
nudis, vibrissis aggregates longissimis. 
IN the description of the Pteromys genibarbis, contained in the Fourth Number 
of these Researches, the peculiarities of the Sciurus sagitta, as they are given in the 
12th Edition of the Systema Naturae from Nordgren, are concisely enumerated.. A 
ferruginous tint mixed with the brown of the upper parts, a membrane extending 
from the head to the anterior extremities, and a size not exceeding a palm in length, 
distinguish that animal both from the Pteromys genibarbis and from the. Pteromys 
lepidus, which is now to be considered. 
The characters which principally distinguish the Pteromys genibarbis from our 
animal, are a large series of bristles, which covers the cheeks in a radiated manner ; a 
