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NORTH AMERICAN FAUNA. 



[No. 10. 



alcoholic cotype (Ko. 1677) agrees witli typical vagrans in size. It now 

 measures: Total lengtli, 95 mm.; tail vertebrae, 43.5 mm.; hind foot, 

 12 mm. 



Specimens examined. — Total number, 104, from the following localities : 



Britisli Columbia: Port Moody, 4; Sumas, 1; Mount Baker Range, 1. 



Washington: SteilacooDi, 4; Olympic Mountains (Lake Cusliman), 11; Sauk, 

 1; Mount Vernon, 1; Hamilton, 1; Avon, 3; Aberdeen, 22; Sboalwater Bay, 1; 

 Easton, 3; Marshall, 7; Wawawai (5 miles northeast), 1. 



Oregon: Salem, 8; Oregon City, 2; Sheridan, 2; Gold Beach, 3; Port Orford, 

 1 ; Florence, 1 ; Fort Klamath, 4. 



California: Crescent City, 3; San Mateo, 1; Monterey, 1; Fort Crook, 10 

 (inclining toward amocnus)', Cassel, 2; Carberry ranch, 5 (intergrade -with 

 arnoenus). 



SOREX VAGRANS DOBSONI Merriam. 

 (PL IX, figs. 8, 8a.) 



Sorex doUoni Merriam, N. Am. Fauna, No. 5, pp. 33-34, PI. IV, fig. 2, August, 1891. 

 Type from Saw Tooth or Alturas Lake, east base Saw Tooth Mountains, Idaho. 



Geographic distribution. — Eocky Mountain region in northern Idaho 

 and western Montana; also isolated mountains in Montana (Big Snowy 

 and Pryor mountains), Wyoming (Big Horn Mts.), and Utah (Wasatch 

 Mts.). Restricted to lower Boreal and upper Transition zones. 



General characters. — Intermediate in size and cranial characters 

 between 8. vagrans and ohscurus; third unicuspid smaller than fourth. 



Color. — Upper parts uniform dull sepia brown with a faint chestnut 

 tinge; under parts ashy gray washed with drab; tail bicolor: dark 

 brown above, drab below. In winter pelage the upper parts are iron 

 gray or ash gray with very little sepia, and the under parts are white 

 or nearly white. 



Cranial and dental characters. — Skull and teeth similar to those of 

 8. ohscurus, but skull slightly smaller; palate narrower; anterior i^art 

 of rostrum more attenuate; unicuspid series decidedly narrower, 

 especially the first and second teeth. Compared with 8. vagrans the 

 skull is larger, particularly the brain case; the molariform teeth also 

 are larger. 



Measurements. — Type specimen: Total length, 105 mm. ; tail vertebrae, 

 47 mm. ; hind foot, 12.5 mm. Average of 7 specimens from type locality 

 (east base of Saw Tooth Mountains, Idaho): Total length, 104 mm.; 

 tail vertebrae, 43.4 mm. ; hind foot, 12.8 mm. 



General remarks. — Sorex dobsoni is the interior form of 8. vagrants; 

 it inhabits the Rocky Mountain plateau, while true vagrans is confined 

 to the coast region and Cascade-Sierra system. Intermediate speci- 

 mens have been examined from Marshall and Wawawai on the elevated 

 sage plain of eastern Washington. Skulls of dobsoni from the Big 

 Horn Mountains have the brain case flatter (more depressed posteri- 

 orly) than those from the adjacent Pryor Mountains. The latter agree 

 with specimens from the Big Snowy Mountains in having the brain 

 case high posteriorly and the teeth heavily i^igmented. The interrela- 



