II. AEROMYS, A NEW GENUS OF FLYING- 

 SQUIRREL. 



By Herbert C. Robinson, C.M.Z.S. and 

 C. BoDEN Kloss, F.Z.S. 



We have recently been fortunate enough to obtain several 

 fresh examples of the rare Flying-squirrel described by 

 Giinther (P.Z.S. 1873 p. 413, pi. xxxvii) as Pteromys tephrotnelas. 

 On examination these prove to possess so many distinct cha- 

 racters as to require the erection of a new genus for the 

 reception of this and the allied species Pteromys phaeomelas, 

 Giinther, from Borneo, which we have also inspected. We 

 have characterized this below and propose that it should be 

 known as 



Aeromys, genus nov. 



Large to medium sized flying-squirrels, having the external 

 appearance of Petaurista and the dentition of the Scinropterus 

 group. 



Tail cylindrical, non-distichous, the base contained in the 

 interfemoral membrane. Antebrachial membrane present. 

 Soles naked except the heel. Digits hairy beneath. 



Skull generally resembling Petaurista but less robust and 

 narrower. Bullae not constricted mesially and more triangular 

 in outline. No palatal spine. Zygomatic plate, as in the 

 Scinropterus group, lacking a pronounced post-orbital point. 



Teeth markedly different from those of Petaurista, more 

 nearly agreeing with Hylopetes. Crowns not flat, with two 

 transverse ridges meeting on an elevated cusp on the inner 

 margin of the upper teeth : no deep transverse notch at the 

 postero-internal angle. Sides of ridges sculptured and 

 wrinkled, p^ well developed, interior to the anterior extremity 

 of /)^. /)■* about equal in area to m^. 



Type — Aeromys tephromelas {Pteromys tephromelas, Giinther) 

 from the Malay Peninsula. 



Other species: Aeromys phaeomelas (Giinther), from 

 Borneo. 



