Mr. O. Thomas on the Genera and 



Range. Nortli America and N.W. Himj 



Type — Sciuropterus {Glaucomys) volans {Mus voJans, 

 Linn.). 



Other species : those of N. America, and also S.fimbriatus, 

 Gray. 



Extraordinary as the above-given range may appear to be, 

 I can find no character of subgeneric importance to separate 

 the large Himalayan ;S^. fimhriatus from the N. American 

 flying-squirrels, while both are equally distinct from the 

 intervening species belonging to the restricted subgenus 

 Sciuropterus. 



Hylopetes, subgen. nov. 



Teeth very much as in Glaucomys^ though there is an 

 increasing tendency, which culminates in the next group, for 

 the enamel to be finely sculptured between and on the sides 

 of the ridges. 



Bullae well inflated, sometimes doubled by the swelling up 

 of the posterior mastoid portion. 



Mammge 6. 



Range. Oriental Region from Nepal to the Malay Islands. 



Type — Sciuropterus [Hylopetes) everetti^ Thos. 



Other species : S. aWoniger, Hodgs. ; nigrt'pes, Thos. ; 

 spadaceus, Bly. ; phayrei^ Bly. ; aurantiacus^ Wagn. ; platy- 

 vrus, Jent. ; phaomelas, Giinth. ; tep)hromelas, Giinth. ; 

 tJiomasi, Hose. 



Petinomys, subgen. nov. 



Teeth with rather lower cusps and ridges than in true 

 Sciuropterus, the enamel rather more elaborately sculptured, 

 and with a more frequent development of accessory cusps, 

 csjiecially at the outer exit of the valley between the two 

 main transverse ridges. 



bkull broad and low, with a short muzzle. Bullae fairly 

 large horizontally, but peculiarly low and flattened, scarcely 

 rising above the general level of the base of the skull, their 

 substance unusually thick and opaque. 



Mammas 4 or 6. 



Range. S. India and Ceylon, Malay Peninsula and islands. 



Type — Sciuropterus {Petinomys) lugens, Thos. 



Other species : S. fuscccopillus, Jerd. ; hageniy Jcnt. ; 

 ma?rens, Mill.; genibarbis, Horsf . ; setosus, Temm.; vorder- 

 manni, Jent. 



I should have been inclined to consider the striking and 

 peculiar flattening of the bullse in this group as a generic 



