_Comparisons._--Smaller with relatively smaller tail and hind feet than _S. v. longicauda_, but resembling it in color. Smaller and paler than _S. v. prevostensis_ with relatively narrower rostrum. Larger, darker, and with relatively longer tail than _S. v. obscurus_. Resembles _S. v. alascensis_ but hind foot smaller and skull relatively narrower. Smaller than _S. v. malitiosus_. _Remarks._--In the northern part of its range _S. v. elassodon_ occurs with _Sorex cinereus_. In the southern part it is the only shrew present. _Specimens examined._--Total number 93. ALASKA: near Killisnoo, Admiralty Island, 2 BS; Kupreanof Island, 15 BS; Petersburg, Mitkof Island, 10 BS; Woewodski Island, 4 AMNH; Kasaan Bay, Prince of Wales Island, 18 BS. BRITISH COLUMBIA: Cumshewa Inlet, Moresby Island, 25 BS; Massett, Graham Island, 6 BS; Queen Charlotte Islands, 13 AMNH. _Marginal Records._--ALASKA: Hawk Inlet, Admiralty Island (Jackson, 1928:131); Kupreanof Island; Mitkof Island; St. John Harbor, Zarembo Island (Jackson, 1928:131); Kasaan Bay, Prince of Wales Island; Duke Island (Jackson, 1928:131). BRITISH COLUMBIA: Massett, Graham Island, Queen Charlotte Islands; type locality; Langara Island, Queen Charlotte Islands (Jackson, 1928:131). ALASKA: Forrester Island (_ibid._); Rocky Bay, Dall Island (_ibid._); Shakan (really on Kosciusko Island) (_ibid._); Point Baker (_ibid._); Kuiu Island (_ibid._); Port Conclusion, Baranof Island (_ibid._). =Sorex vagrans prevostensis= Osgood _Sorex longicauda prevostensis_ Osgood, N. Amer. Fauna, 21:35, September 26, 1901. _Sorex obscurus prevostensis_, Elliott, Field Columb. Mus. Publ. 105, zool. ser. 6:450, 1905. _Type._--Adult male, skin and skull; No. 100618, U. S. Biol. Surv. Coll.; obtained on July 3, 1900, by W. H. Osgood from north end of Prevost Island (Kunghit Island on some maps) on coast of Houston Stewart Channel, Queen Charlotte Islands, British Columbia. _Range._--Known only from the type locality. _Diagnosis._--Size medium; measurements of two specimens from the type locality are: total length, 132, 142; tail, 53, 59; hind foot, 14, 15. Color dark. _Comparisons._--Larger and darker than _S. v. elassodon_. Resembles _S. v. longicauda_ but darker, tail relatively somewhat shorter on the average and rostrum relatively slightly broader. _Specimens examined._--Total number, 14. BRITISH COLUMBIA: Prevost Island, Queen Charlotte Group, 14 BS. =Sorex vagrans alascensis= Merriam _Sorex obscurus alascensis_ Merriam, N. Amer. Fauna, 10:76, December 31, 1895. _Sorex glacialis_ Merriam, Proc. Washington Acad. Sci., 2:16, March 14, 1900, type from Point Gustavus, east side of entrance to Glacier Bay, Alaska. _S[orex]. alascensis_, Merriam, Proc. Washington Acad. Sci., 2:18, March 14, 1900. _[Sorex glacialis] alascensis_, Elliott, Field Columb. Mus. Publ. 45, zool. ser. 2:372, 1901.