HETEROMYIDJE 169 



some extent. Tlieir harvest is irregular and short, and the main 

 dependance must be on stored seeds the greater part of the year. 

 Much loss through starvation must occur after unfavorable sea- 

 sons. The breeding season is spring, April to June. The usual 

 number young is four and five, but I have taken several females 

 containing seven foetuses. In favorable seasons tvi^o litters of 

 young appear to be raised. 



Perognathus Stephens! Merriam. 



STEPHENS POCKET-MOUSE. 



Similar to penicillatus but very much smaller; skull short; 

 rostrum broader. 



Type locality, the northwestern arm of Death Valley, Cali- 

 fornia. 



Known only from two examples which I caught in that part 

 of Death Valley, known locally as Mesquit Valley. It is prob- 

 ably a dwarf subspecies of penicillatus. 



Perognathus fallax Merriam. (Deceptive.) 



SHORT-EARED POCKET-MOUSE. 



Above brownish buff mixed with black; lateral line buff, us- 

 ually well defined; white spot at base of ear small and faint; an 

 indistinct dusky crescent at base of whiskers; feet and lower 

 parts buffy white; tail pencillate and terminal third crested, up- 

 per side brownish becoming dusky terminally, white below; skull 

 well arched; mastoids of moderate size; rostrum rather slender; 

 interparietal large, wide; outer sides of nasals parallel to ends 

 posteriorly; ears small, round; pelage coarse and mixed with 

 long coarse spines on the rump and hips, those of the rump 

 black and on the hips white. 



Length about 185 mmi (7.30 inches); tail vertebrae no 

 (4.33) ; hind foot 25 (i) ; ear from crown 7.5 (.30). 



Type locality, Reche Canon, San Bernardino Valley, Cali- 

 fornia. 



