278 Univfrsity of Califoniia Piihlicaiioiis in Zoology. [Vol. 7 



no. 81 -17) this is not diseernible. Four specimens have one or 

 more small spots of white dorsally (nos. 8121-8124). No. 8147, 

 though seeming to have assumed the new pelage dorsally for the 

 most part, has the pelage ventrally in an al)normally worn con- 

 dition. 



Juvenals of olivaccus, as shown by nine examples, differ from 

 the adults chiefly in their mouse-gray coloration dorsally. 



Distribution. — Specimens were secured as follows : Quimi 

 River Crossing (altitude 4100 feet), 10; Big Creek Ranch (4350 

 feet), 9; Big Creek (7000 feet), 5; head of Big Creek (8000 feet), 

 1 ; Duifer Peak (8400 feet), 1 ; Leonard Creek (6500 feet), 7. All 

 of these localities, except Quinn River Crossing, are in the Pine 

 Forest Mountains. 



The present records, while not extending the known range of 

 the species geographically, probably do have this effect zonally. 

 Osgood refers olivaceus to the Upper Sonoran. We found the 

 species extending in small numbers into very high Upper Sonoran 

 and following sage slopes into Lower Transition. 



In order to ascertain whether there was any tendency to local 

 variation at altitudes above those of the Great Basin plateau at 

 large. I segregated all the specimens from the higher parts of the 

 mountains from those of the desert fiat, and tabulated their 

 measurements (see table of external and cranial measurements). 

 I was thus enabled to prove definitely that, at least so far as our 

 material goes, there is practically no variation in size (and there 

 is none in coloration) with altitude. 



It is extremely probable that Pero<j)iallnis parvus oliraccus 

 intergrades with P. p. parvus to the north (Osgood records speci- 

 mens of parvus from Tumtum Lake, Harney County, Oregon, 

 which is not far north of Quiini River Crossing, and in the same 

 general faunal area), with /'. />. mollipilosus to the west, and 

 possibly with P. p. niayrudcrvi^sis to the soutli. 



Habits. — The cheek-pouches of a pocket mouse taken on May 

 liJ at Quinn River Crossing were filled with green seeds. 



The animals live in shallow burrows. In several instances 

 spccinieiis were caught at tlic mouths of small holes. 



While Pt ro(j)ia(lius p. olivaceus is not limited in its distribu- 

 tion to tile neighborhood of streams, we were more successful 



