76 CALIFORNIA MAMMALS. 



Judging from my limited experience with this species they occur 

 in open ground principally. I saw none in rocky places. Those 

 I saw were very shy. 



Genus Eutamias Trourssart. (Good or typical; a 



steward. ) 



Skull light and thin, moderately arched in upper outline ; 

 postorbital processes small and slender; penultimate premolar 

 present but small, rarely functional; anteorbital foramen small, 

 n\al, with a prominent tubercle at its lower edge; internal cheek 

 pouches large; ears rather large; tail about as long as body with- 

 out the head ; inner toe on front foot rudimentary ; pelage striped, 

 rather long"; mammas eight; habit terrestrial and fossorial; size 

 small. 



Dental formula, I, i — i ; C, o — o; P, 2 — i ; M, 3 — 3X2=22. 



The species of this genus are very much alike, and even 

 experts are sometimes in doubt what species a given specimen 

 should be assigned to when material for comparison is not avail- 

 able. The skulls show no differences of sufficient value to be of 

 much use in separating species, and there is considerable in- 

 di\-idual variation in externals. More or less marked seasonal 

 variations in pelag'e help complicate the situation. The group 

 is very "plastic," being usually susceptible to modification from 

 climatic causes, in the directions of size and color; hence differ- 

 ences in climatic through differences of altitude, isolation on 

 mountain ranges separated from other mountains by climatic 

 barriers, etc., have brought about a separation of the genus into 

 a number of closely related forms. From the nature of these 

 causes the lines of separation are often indistinct. 



The following characters are common to all Californian 

 species in fresh pelage, in old worn pelage some points will be 

 lacking": 



Five dark stripes on the back from the neck or shoulders 

 to the rtmip, enclosing four light stripes in decided contrast; 



