4 Proceedings of the Biological Society of Washington. 



Measurements. — Head and body, 178; tail, 111; hind foot, 38 (36); 

 condylobasal length of skull, 38.3 (36.2)*; zygomatic breadth, 25.7 (24.2); 

 mastoid breadth, 20.2(19.0); interorbital constriction, 8.8 (9.0); rostral 

 breadth at front of nasals, 6.5 (6.8); nasal, 13.5 (12.8); diastema, 8.0 

 (8.2) ; mandible, 24.0 (23.2); maxillary toothrow, 7.4 (7.4) ; mandibular 

 toothrow, 7.2 (7.2). 



Remarks. — In his field notes, Mr. Amory writes of the flying-squirrel: 

 "Not found south of the Verkhne Kolymsk region. Last year it was 

 scarce, like the tree squirrel, but usually it is plentiful on the upper 

 Kolyma. This beautiful little skin is too tender to have a commercial 

 value, and the Yakut and Russian merchants do not trade it. But it has 

 a local value of ten kopeks, and is sometimes made up into shirts or 

 parkas." 



Specimen examined. — The type. 



* Cranial measurements in parenthesis are those of an adult male Petromys volans 

 volans from Finland, No. 1. 6. 9. 1 British Museum (see Cat. Mamm. Western Europe 

 Brit. Mus., p. 946. November, 1912. 



