1903.] Allen, Mammals from Northern British Columbia. 55 J 



21. Microtus macrurus Merriam. OLYMPIC VOLE. 



Microtus macrurus MERRIAM, Proc. Acad. Nat. Sci. Phila., 1898, 353. 

 Oct., 1898. Lake Cushman, Olympic Mountains, Washington. 



A single specimen, a 'young adult' male, from Kuprea- 

 nof Island, southeastern Alaska, taken November 10. Total 

 length, 165; tail vertebrae, 61; hind foot, 20; ear, 14. Above 

 very dark gray brown, or blackish brown, with an almost im- 

 perceptible yellowish suffusion; below dark gray, the longer 

 hairs tipped with whitish. 



22. Fiber spatulatus Osgood. NORTHWEST MUSKRAT. 



Fiber spatulatus OSGOOD, N. Am. Fauna, No. 19, Oct. 6, 1900, 36. 

 Lake Marsh, Northwest Territory, Canada. 



One specimen, an old male, Shesley (Government telegraph 

 station), September 5. 



This specimen greatly exceeds the measurements given for 

 F. spatulatus, but agrees with the description of this species in 

 all other characters. As shown by the massive, heavily ossi- 

 fied skull, the animal was a very old male. The external 

 measurements are: Total length, 583; tail vertebras, 290; 

 hind foot, 78; ear, 23. Skull: Total length, 68; basal length, 

 64.5; zygomatic breadth, 43; length of nasals, 24; least 

 width of nasals posteriorly, 3 ; greatest width anteriorly, 11.2; 

 alveolar length of molar series, 15 ; length of crown surface, 13. 



A specimen of corresponding age and sex from Hastings, 

 Westchester Co., N. Y., measures as follows: Total length, 

 591; tail vertebras, 274; hind foot, 83. Skull: Total length, 

 65; basal length, 62; zygomatic breadth, 39.6; length of 

 nasals, 22; least posterior width of nasals, 2.6; greatest 

 anterior width of nasals, 8.6; alveolar length of molar series, 

 16; length of crown surface of molar series, 15. The Shesley 

 skull thus exceeds in linear dimensions and greatly in massive - 

 ness any skull in a very large series of eastern Muskrats; and 

 also exceeds the type specimen of F. spatulatus by about 20 

 per cent, in total length, and about 7 per cent, in the principal 

 skull measurements. 



