46 Description of a New Species of Dipodomys. [ Jan. 
to nearly its best speed to overtake it. I once saw a D. phillipst 
run some forty or fifty yards in broad daylight, and have often 
seen them skurry away from camp in the moonlight when I 
happened to alarm them by some movement. 
‘In places where much camping is done, such as by springs on 
the principal roads from one mining camp to another, the pocket- 
rats are in the habit of coming about the wagons at night to 
pick up the grain scattered by the horses, etc., becoming com- 
paratively tame, as no one harms them. I never knew a dog to 
catch one, for they can get under way very quickly, and in such 
places they have many holes, perhaps for such emergencies, and 
they immediately vanish in the nearest. In feeding they often 
rise to a more or less erect posture, apparently to get a better 
view of their surroundings. In the house I have seen them 
stand erect on the tail and the toes of the hind feet, thus 
forming a secure tripod; at such times they walk about several 
steps, sidewise as well as forward, with as much ease as a man. 
D. phillipsi is the shyest ; they dislike to be handled, and do not 
often come near me when out in the room. D. desert does not 
seem to dislike handling, but they will not yet come to me when 
called, though when running about the room they pay no atten- 
tion to me, running across my feet, etc. Sometimes when I come 
in the room they will presently come quite close to me, ap- 
parently from a mild curiosity to see what I am doing. They 
appear to be almost devoid of fear of other animals. The first 
time I put the cat in the room they came to the front, putting 
their noses against the wire netting to look at the cat, which was 
greatly vexed that she could not get at them. In this instance 
the D. phillipsi remained at the back of their cages. 
So far none of my captives will drink water. They will eat 
of vegetables, such as sweet potatoes, the leaves of beets and 
cabbages. It is probable that they obtain sufficient moisture 
from such sources. The principal food seems to be seed and ` 
= They consume but little more than a heaping table- 
each of wheat or barley in twenty-four hours, and one 
or two square inches of beet or cabbage leaves, so they are not 
heavy eaters. For the first two or three days I had them they 
-~ probably ate double this amount, but as they had been on short 
allowance for some weeks they were more than usually hungry. 
_ ‘The seeds on which they depend in a state of nature had been 
