_Zapus hudsonius ontarioensis_ Anderson (1942:59) from eastern Ontario was based chiefly, in comparison with _Z. h. canadensis_, upon, "dorsal stripe less distinct and sides somewhat duller yellowish with more admixture of blackish hairs." Examination of 68 of the 69 specimens from the type locality shows that 58 are subadult and in subadult pelage. Individuals which are adult are indistinguishable in color of pelage and in cranial features from comparable material from southern Quebec. _Z. h. ontarioensis_ is, therefore, considered to be a synonym of _Z. h. canadensis_. _Specimens examined._--Total, 123, distributed as follows: NEW YORK: _Franklin Co._: Spectacle Pond, Brighton Township, 2 (AMNH). _Genesee Co._: Elba, 2 (Clev. MNH). ONTARIO: Schreiber, 2 (NMC); Franz, 5 (MVZ); Pancake Bay, Algoma District, 68 (NMC); Maclennan, Algoma District, 3 (ROM); Cache Lake, Algonquin Park, 1 (MVZ); _Experimental Farm, Ottawa_, 1 (NMC); _Dows Swamp, Ottawa_, 1 (NMC); Apple Hill, 1 (NMC); Clear Lake, Arden, 1 (NMC); _Athens_, 1 (NMC); _Aurora_, 4 (Clev. MNH); Pattageville, Toronto, 1; _Lorne Park, Toronto_, 1 (NMC); _Credit_, 2 (NMC); Pickering, 1 (MVZ); _Preston_, 1 (NMC); St. Thomas, 1 (NMC). QUEBEC: _Notre Dame de la Dore_, 3 (NMC); 1/2 mi. N Mistassini Post, 1 (NMC); Lake Albanel, 1 (NMC); St. Felicien, 3 (NMC); Valcartier, 8 (NMC); Kiamika Lake, 4 (NMC); _Ste. Veronique_, 2 (NMC); _Val Jalbert_, 2 (NMC); _St. Methode_, 1 (NMC). _Marginal records._--Quebec: 1/2 mi. N Mistassini Post; Valcartier. New York: Spectacle Pond, Brighton Township; Elba. Ontario: St. Thomas; Pancake Bay, Algoma Dist.; Franz; Schreiber. Quebec: Kiamika Lake. =Zapus hudsonius hudsonius= (Zimmerman) _Dipus hudsonius_ Zimmerman, Geog. Geschichte d Menschen u. vierfussigen Thiere, 2:358, 1780. _Dipus labradorius_ Kerr, Animal Kingdom:276 (based on the Labrador Jerboid Rat of Pennant, 1781--but Preble, N. Amer. Fauna, 15:11, August 8, 1899, states that the specimen came from Hudson Bay), 1792. _Gerbillus canadensis_, Desmarest, Mammalogie, 2:321, 1822. _Gerbillus labradorius_, Harlan, Fauna Amer., p. 157, 1825. _Meriones labradorius_, Richardson, Fauna Boreali-Americana, 1:144, 1829. _Jaculus labradorius_ Wagner, Suppl. Schreber's Saugthiere, 3:294, 1843. _Zapus hudsonius hudsonius_, Preble, N. Amer. Fauna, 15:15, August 8, 1899 (part--the part from Northwest Territory, Ontario, Michigan, northern Wisconsin and northern Minnesota). _Zapus hudsonius alascensis_, Osgood, N. Amer. Fauna, 19:38, October 6, 1900. _Type._--Type specimen not known to be in existence; from Hudson Bay, locality now considered to be Fort Severn, Ontario (see Anderson, 1942:37). _Range._--Central Alaska southeastward to central Ontario, northern Minnesota, northern Wisconsin, and upper peninsula of Michigan. See fig. 47. Zonal range: Hudsonian, Canadian, and into Transition.