HETEROMYID.E 171 



eat no green plants or roots that I gave it and would not touch 

 water. During the last three years of its life I gave it only dry 

 barle}' or dr}- wheat and no water. It seemed to prefer the 

 wheat. It is a mystery to me how such an animal can live for 

 years and thrive on dry grain without water or moisture in any 

 form, but this one certainly did. Three or four times a year I 

 emptied the box and put in clean dry sand and set it in the 

 corner of the hall, where it was perfectly dry, and put nothing 

 more in the box but dry grain and a little cotton, of which the 

 Pocket-Mouse made a globular nest. 



If taken out of the box after dark and turned loose on the 

 floor the Pocket-Mouse moved actively about a few minutes, 

 usually by short, deliberate jumps; but if frightened it leaped 

 two feet or more. After it had satisfied its curiosity it crept 

 into a dark place behind some piece of furniture. If turned out 

 on the floor in the daytime it hunted a dark place if allowed to, 

 and was easily caught, but after dark I had to corner it to catch 

 it. When captured this Pocket-Mouse appeared to be fully 

 adult. It died in the summer of 1894, during my absence from 

 home. It therefore, was at least five years old at the time of its 

 death and probably older. 



Perognathus fallax pallidus AIearns. (Pale.) 



PALLID POCKET-MOUSE. 



Similar to fallax in size and proportions but paler, the in- 

 termixed dark hairs being fewer and brown instead of black. 



Type locality, Mountain Spring, San Diego County, Cali- 

 fornia. 



The habitat of Pallid Pocket-Mice is the dry, cactus grown 

 slopes of the mountains bordering the western side of the Colo- 

 rado Desert, in San Diego County and northern Lower Califor- 

 nia. They do not seem to be common anywhere. They live 

 among the rocks in the gulches and on the hillsides. They are 

 associated with the Spiny Pocket-Mice in the lower part of the 



