460 University of California Publications in Zoology — (Vou. 17 
individual variation is great. Two examples from Siskiyou (nos. 56737, 
56738, Biol. Surv. Coll.) are larger than the others of the series and 
have conspicuously heavier crania. Examples of rufa from Ashland 
Peak, also, are above the average in size, and show a likeness to rainieri 
in certain skull characters. 
Intergradation between rufa and californica is best shown by sev- 
eral examples from Canyon Creek, California. These specimens com- 
bine the coloration and shortness of the rostrum of rufa with the 
squarer zygomatic arches and, in one ease, the distinctive nasal out- 
line of californica. 
The distribution of aplodontias in northwestern California will 
bear additional intensive research. Specimens from the Trinity 
Mountains, east of Hoopa, are nearly typical of rufa from farther 
inland, although they show a slight tendency eranially in the direction 
of humboldtiana. Real intergradation is indicated, however, by three 
specimens from the divide between the Klamath and Trinity rivers, 
twelve miles north of Hoopa Post Office. Of these, an adult female 
(no. 98745, Biol. Surv. Coll.) both in eranial and external characters 
resembles humboldtiana; one young animal also (no. 97291, Biol. Surv. 
Coll.) resembles humboldtiana; while the third (no. 97290, Biol. Surv. 
Coll.), also a young animal, is nearest rufa. Examples referred to rufa 
have been taken in Hoopa Valley, as well as at Rio Dell, Humboldt 
County, California. 
A tendency toward pattern formation is noted in specimens from 
Sauk, Washington. Extensive irregular patches of white beneath are 
conspicuous in several examples. 
Aplodontia rufa olympica Merriam 
Olympie Aplodontia 
Aplodontia olympica Merriam (1899), p. 20. 
Haplodontia olympica, Elliot (1899), pp. 251-253. 
Type.—Male, young adult, no. 89549, U. S. Nat. Mus., Biol. Surv. 
Coll.; Quiniault Lake, Olympic Mountains, Washington; July 24, 
1897 ; collected by R. T. Young; orig. no. 309; stuffed skin, with skull 
and jaws, all in good condition. 
Specimens Examined.—Total number 29, from the following 
localities : 
