Interbreeding in the wild between _Z. t. orarius_ and _Z. t. eureka_ probably does not take place, because these subspecies are separated by terrain unsuited to jumping mice.
_Specimens examined._--Total, 29, all from California, distributed as follows: _Marin County_ (MVZ): 3 mi. W Inverness, 300 ft., 14; _5 mi. NNE Point Reyes Lighthouse_, 12; _W end Elk Valley, 10 ft._, 1; West Portal, Fort Barry, 2.
_Marginal records._--California: 3 mi. W Inverness, 300 ft.; West Portal, Fort Barry.
_Zapus trinotatus Rhoads_, Proc. Acad. Nat. Sci. Philadelphia, 1894:42, January 15, 1895.
_Jaculus hudsonius_, Baird, Repts. Expl. and Surv. 111, 8 (pt. 1): 433, July 14, 1858 (part--the part from Washington).
_Zapus hudsonius_, Coues, Bull. U. S. Geol. and Geog. Surv. of the Territories, 2nd ser., No. 5:260, 1877 (part--the part from Steilacoom [Pierce County], Washington).
_Zapus imperator_ Elliot, Field Columbian Mus., publ. 30, zool. ser., 1:228, February 1, 1899, type from Siegs Ranch, Elwah River, Clallam County, Washington.
_Zapus princeps trinotatus_, Dalquest, Univ. Kansas Publ. Mus. Nat. Hist., 2:371, April 9, 1948.
_Type._--Male, adult, skin and skull, No. 360, S. N. Rhoads Coll.; Lulu Island, mouth of Frazer River, British Columbia; obtained on May 31, 1892, by S. N. Rhoads (type in Philadelphia Acad. Nat. Sci.).
_Range._--Pacific coastal region from Requa, Del Norte County, California, north in Oregon west of the Cascades, and in Washington including the Cascades; to southwestern British Columbia.
_Description._--Size large; back from near Ochraceous-Buff to near Tawny with admixture of black hair forming broad dorsal band; sides lighter than back from near Ochraceous-Buff to near Tawny; lateral line usually distinct; belly white, sometimes with faint suffusion of ochraceous on lower throat and upper chest; tail bicolored, brown above, white to yellowish-white below; ears dark, sometimes flecked with color of sides, edged with ochraceous; feet grayish-white above; palatal bridge relatively short; incisive foramina relatively long; condylobasal region long; zygomatic width great; braincase relatively broad; distance from incisors to postpalatal notch relatively great.
_Comparisons._--For comparisons with _Zapus trinotatus montanus_ and _Zapus trinotatus eureka_ see accounts of those subspecies.