410 MR. OLDFIELD THOMAS ON MAMMALS [Apr. 23, 



Dimensions of the type (immature) : — 



Head and body 125 mm. ; tail 110 ; hind foot 36-5 ; ear 20-5. 



Skull — greatest length 37 mm. ; basilar length 28 ; zygomatic 

 breadth 22 ; intero]-bital breadth 7 ; palatilar length 16*2 ; 

 palatal foramina 4-8 ; length of bullse lO'l ; length of upper 

 tooth-series 7'2. 



Hah. & Tyjie as above. 



This Flying- Squii'rel seems to be a local race of the Russian 

 and Siberian 8. russicus, rather than any relation of S. momonga, 

 though its colour is exactly as in the latter, instead of the clearer 

 grey of its ally. Satunin's S. huechneri *, from Kansu, has a 

 shorter hind foot and a more rufous colour. 



10. SCIURUS VULGARIS RUPESTRIS t, Subsp. U. 



2 . 812. 15 miles N.W. of Korsakoff, Saghalien. Sea -level. 



S . 927. $ . 952-958. Darine, 25 miles N.W. of Korsakoff. 

 200'. 



S . 944. $ . 945. Mts. 35 miles N.W. of Korsakoff. 300' & 

 1000'. 



Quite like S. v. orientis, in summer pelage, but markedly 

 smaller throughout. Winter pelage not represented. 



Colour in summer as in orientis, but there appears to be a 

 greater proportion of melanism, for not one of the six specimens 

 is unaffected in this way. The least affected (ISTo. 927, the type) 

 has the feet and flanks blackish, while the only one (IsTo, 812) 

 which has the feet and flanks reddish, has the back of a very 

 darker colour. The back of the type is rather redder than 

 " Front's brown." 



Skull decidedly smaller than in 07<entis, 3-4 mm. less in 

 extreme length, and the three true molars about half a millimetre 

 less in combined length. This last point is important, as several 

 of the specimens are immature, so that their full size can only be 

 gauged by their teeth. 



Dimensions of the type (slightly immature) : — 



Head and body 190 mm. ; tail 174 ; hind foot 55 ; ear 32. 



Skull— greatest length 48-8 mm. ; basilar length 37 ; length of 

 true molar series 6*7. 



Dimensions of No. 944, a fully adult male : — 



Head and body 208 mm. ; tail 178 ; hind foot 57 ; ear 32. 



Skull — greatest length 50-7 mm. ; basilar length 39-5 ; length 

 of nasals 14-3 ; breadth of brain-case 24 ; palatilar length 22-5 ; 

 combined length of p* and three true molars 8-9. 



Type. Immature male. B.M. No. 7.2.5.26. Original number 

 927. Collected 20th August, 1906. 



In a group where the main distinctions have been made on 

 colour, it is somewhat embarrassing to have to deal with this 



* Ann. Mus. St. Petersb. vii. 1902, p. 3 (1903). 



t I am informed by Dr. Knud Andersen that Saghalien is a modification of a 

 Chinese word meaning " cliff at (the mouth of) Amur." 



