150 Proceedings of the Biological Society of Washington. 



moderately heavy, molariform teeth rather deeply emarginate posteriorly ; 

 third unicuspid larger than fourth. 



Measurements. — Type (adult male) : Total length, 127; tail vertebrae, 

 52; hind foot, 14. Skull: Type (adult male; teeth slightly worn): 

 Condylobasal length, 24.0; palatal length, 7.2; breadth of cranium, 9.3; 

 interorbital breadth, 3.9; maxillary breadth, 5.3; maxillary tooth row 

 (anterior edge of second upper incisor to posterior edge of last upper 

 molar measured at alveolar border), 6.8. 



Remarks. — Specimens typically representative of S. f. umbrosus have 

 been examined only from Nova Scotia and the coast region of New 

 Brunswick (Hampton). Intergradation with S. f.fumeus is indicated in 

 specimens of umbrosus from Maine and western New Brunswick, while 

 certain specimens referred to the subspecies fumeus from New Hamp- 

 shire, Vermont, western Massachusetts, and even the Adirondacks of 

 New York, show an approach towards umbrosus. 



