_Diagnosis._--Size small for the species; measurements of two topotypes are: total length, 105, 106; tail, 39, 40; hind foot, 12, 13. Upper parts in winter Chaetura Black or near Fuscous-Black; underparts brownish; upper parts in summer near (17'_m_) Mummy Brown; underparts with a decided buffy wash, near (15'_d_) Light Ochraceous Buff; rostrum relatively large; maxillary tooth-row relatively long; teeth relatively large. _Comparisons._--Darker ventrally, both summer and winter, than _S. v. vagrans_; slightly more reddish dorsally in summer pelage than _S. v. vagrans_, rostrum and teeth relatively larger; smaller externally than _S. v. paludivagus_, paler; skull longer, narrower cranially and broader rostrally. _Remarks._--This subspecies seems to be restricted to salt marshes where it occurs with _Sorex ornatus_. _Specimens examined._--Total number, 12. CALIFORNIA: _San Francisco Co._: San Francisco, 4 BS. _Alameda Co._: West Berkeley, 1 BS; Berkeley, 1 BS; Dumbarton Point, 1 KU. _San Mateo Co._: San Mateo, 2 BS. _Santa Clara Co._: Palo Alto, 3 BS. _Marginal records._--CALIFORNIA: Berkley, _Elmhurst_; _Palo Alto_; San Mateo. =Sorex vagrans paludivagus= von Bloeker _Sorex vagrans paludivagus_ von Bloeker, Proc. Biol. Soc. Washington, 52:93, June 5, 1939. _Type._--Adult male, skin and skull; No. 5053, Los Angeles Museum of History, Science and Art, obtained on November 3, 1938, by Jack C. von Bloeker, Jr., from salt marsh at mouth of Elkhorn Slough, Moss Landing, Monterey Co., California, original no. 9456. _Diagnosis._--Size medium for the species; average and extreme measurements of 6 topotypes are: total length, 115 (113-118); tail, 46.5 (42-48); hind foot, 14.5 (14-15) (von Bloeker, 1939:94). In winter nearly black dorsally, deep mouse gray ventrally; in summer nearly as dark dorsally as in winter, hairs of venter tipped with Clove Brown; skull short, relatively broad cranially and relatively narrow rostrally. _Comparisons._--For comparison with _S. v. halicoetes_ see account of that subspecies. _Remarks._--This subspecies, occurring at the limits of the range of the species, is uncommon in most collections. Seven specimens were available for the original description. The summer pelage is not completely described in the original description, but is stated to be darker than the winter pelage of _S. v. vagrans_, and must thus be considerably darker than the summer pelage of _S. v. halicoetes_. Two specimens in the Museum of Vertebrate Zoology, from San Gregario, referred by Jackson to _S. v. halicoetes_, were included in the present subspecies by von Bloeker. _Specimens examined._--None. _Records of occurrence_ (von Bloeker, 1939:94).--CALIFORNIA: _San Mateo Co._: San Gregario. _Monterey Co._: Seaside; mouth of Salinas River; Moss Landing. _Marginal records._--CALIFORNIA: San Gregario; Seaside. =Sorex vagrans vancouverensis= Merriam _Sorex vancouverensis_ Merriam, N. Amer. Fauna, 10:70, December 31, 1895.