1920] Howell: A Study of the California Jumping Mice 229 



List of Forms of Zapus Occurring in California, with Type Localities 



Zapus trinotatus eurel'a, new subspecies Fair Oaks, Humboldt County, California 



Zapus orarius Preble Point Eeyes, Marin County, California 



Zapus paoificus alleni Elliot Pyramid Peak, Eldorado County, California 



Zapv^ major Preble Warner Mountains, Oregon 



Key to the California. Forms of Zapus 



1. Underparts strongly suffused with the color of the sides. 



2. Foot averaging more than 32.5 mm. ; tail sharply bicolor and 60 per cent 



of total length; skull usually more than 24 mm. long eureka 



2'. Foot averaging less than 32.5 mm. ; tail not sharply bicolor and less 

 than 5'8 per cent of total length; skull usually less than 24 mm. 



long orarius 



1'. Underparts white. 



3. Coloration of sides bright ochraeeous buff alleni 



3'. Coloration of sides dull taAvny olive major 



Zapus trinotatus eureka, new subspecies 

 Humboldt Jumping Mouse 



Type. — Female adult, skin and skull; no. 11703, Mus. Vert. Zool. ; Fair Oaks, 

 Humboldt County, California; August 27, 1910; collected by J. Dixon; original 

 no. 1743. 



Range. — Northwestern coast region of California, from Mendocino 

 City, Mendocino County, north at least through Humboldt County. 

 Number of specimens examined, 24, from the following localities in 

 California. Specimens in Mus. Vert. Zool., unless otherwise indicated. 

 Mendocino Countj': Mendocino City, 1. Humboldt County: Eureka, 

 11; Fair Oaks, 6; Areata, 5; Loleta, 1 (coll. D. R. Dickey). 



Diagnosis. — A rather large, ochraceous-bellied Zapus, with sharply 

 bicolor tail, nearest to Z. t. trinotatus (5 skins from Seattle and 3 

 from Puyallup, Washington; D. E. Brown and A. B. Howell collec- 

 tions; assumed to be typical). From that species it differs in having 

 larger bullae and pterygoid fossae, narrower basioccipital, and longer 

 rostrum and nasals, the latter being wider posteriorly. The brain- 

 case is slightly less inflated and the bases of the anteorbital foramina 

 are heavier. Underparts more suffused with the color of the sides. 



External characters. — Collectors' measurements of all available 

 adults indicate that eureka has a longer foot than has trinotatus, but 

 my own measurements of museum specimens fail to substantiate this. 

 In eureka and trinotatus in early fall the general color effect is close 

 to tawny olive, and there is little difference in the coloration of the 



