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NORTH AMERICAN FAUNA. 



[No. 10. 



Cranial and dental characters. — Skull similar to that of ohsciiruSj but 

 larger (averaging 20 mm. in length and 9 mm. in breadth); first and 

 second unicuspids very large and broad, diii'ering markedly from any 

 known species. 



Measurements. — Average of 9 specimens from type locality: Total 

 length, 129 mm.; tail vertebrae, 57 mm.; hind foot, 15.1 mm. 



General remarlcs. — After Sorex pacificus, S. hairdi is the largest of 

 the west American Shrews of the restricted genus Sorex. Externally 

 it resembles its geographical neighbor, longicauda, from which it 

 differs strongly in the large size of its anterior unicuspidate teeth. 



The species is remarkable in several respects. Geographically it is 

 restricted to the coast of Oregon near Astoria, on the south side of the 

 mouth of the Columbia River. On the north side of the river it is 

 replaced by 8. longicanda, a closely related si)ecies, whose affinities 

 have been already discussed. It seems peculiarly appropriate that 

 this large and handsome Shrew should perpetuate the name of Professor 

 Baird, the pioneer in the study of west American Shrews. 



SOREX TROWBRIDGII Baird. 

 (PI. VII, figs. 4, Aa.) 

 Sorex trowhridgii Baird , Mamm., N. Am. pp. 13-15, 1857. 



Ty2^e locality. — Astoria, mouth of Columbia River, Oregon. 

 Geographic distrihution. — Western Washington and Oregon, west of 

 Cascade Range. 



General characters. — Size, rather large; tail long; ears conspicuous; 

 color dark slate or sooty plumbeous, with no brownish or chestnut. 

 Resembles S. montereyensis of California, but differs in marked cranial 

 and dental characters. 



Color. — Upper parts blackish slate or sooty plumbeous; under parts 

 dull plumbeous; tail sharply bicolor: blackish above, whitish beneath; 

 feet flesh color. 



Cranial characters. — Contrasted with S. montereyensis^ the only species 

 with which it requires comparison, the skull of S. troivbridgii is thinner 

 and more ^papery,' the brain case more globular, the palate much nar- 

 rower. The molariform teeth and first and second unicuspids are de- 

 cidedly smaller and narrower. The large upper premolar in particular 

 is very much smaller than in montereyensis. 



Measurements. — Average of 3 specimens from Astoria, Oregon (type 

 locality) : Total length, 121 mm. ; tail vertebrae, 57.7 mm. ; hind foot, 

 13.7 mm. Average of 5 specimens from Olympic Mts., Washington: 

 Total length, 120 mm.; tail vertebrae, 57.8 mm. ; hind foot, 13 mm. 



General remarlxs. — Sorex trowhridgii may be distinguished at a glance 

 from all other American Shrews, except the related S. montereyensis^ by 

 its large size, sooty plumbeous color, and long, sharply bicolor tail. 

 The characters that distinguish it from montereyensis have been pointed 

 out in the above diagnosis. 



