KANGAEOO BATS 149 



rats are loath to come forth), and got reports of the presence of the animals 

 in fields near the town of Mount Bullion. It was our experience that this 

 chaparral-inhabiting species was more difficult to trap than those which 

 live on the sandy plains and deserts. Furthermore, the population of 

 heermanni is sparser than that of the other species; perhaps two to the 

 acre would represent the population on favorable slopes. In a few places, 

 as about clearings in the chaparral, there are probably somewhat more than 

 the number indicated. 



Mono Kangaroo Mouse. Microdipodops polionotus Grinnell 



Field characters. — Body size about that of House Mouse; tail about equal to head 

 and body, smoothly haired, but without any tuft; forefeet normal, hind feet relatively 

 large; a fur-lined pouch on each cheek opening alongside of mouth; ears small and 

 rounded. (See pi. 26d.) Head and body 2i^ to 3% inches (64-83 mm.), tail 2% to 

 31/^ inches (72-88 mm.), hind foot about 1 inch (23-25 mm.), ear from crown % inch 

 (8-10 mm.); weight about % ounce (10.6-12.5 grams). General coloration above sandy 

 buff; whole under surface pure white. 



Occurrence. — Eecorded from Yosemite section only at old Salmon ranch near Mono 

 Lake, east of Sierra Nevada. Lives in dry sandy areas, making burrows in ground at 

 bases of bushes. Nocturnal. 



The Mono Kangaroo Mouse is an inhabitant of the dry Great Basin 

 territory east of the Sierra Nevada. It was found by our party at only 

 one locality, near the old Salmon ranch adjacent to Mono Lake. Four 

 specimens were taken on the night of June 19, 1916, in a dry sandy area 

 a hundred yards or more up from the lake margin. Other areas which to 

 the naturalist's eye were exactly the same as to soil, slope exposure, and 

 flora Avere unproductive when tested by trapping. 



Allen Jumping Mouse. Zapus pacificus alleni Elliot 



Field characters. — Body size somewhat larger than that of House Mouse; tail very 

 long, one-third longer than head and body; tail almost bare of hairs, and scaly (pi. 26a). 

 Front surface of upper incisor teeth grooved. Head and body 3% to 4 inches (86-102 

 mm.), tail 4% to 51/2 inches (120-140 mm.), hind foot 1% to 1% inches (28-33 mm.), 

 ear from crov^^l % to % inch (12-16 mm.) ; weight about % to % ounce (18-24.5 

 grams). Coloration above bright reddish yellow with a dark tract along middle of 

 back; whole under surface pure white; tail and feet dusky. 



Occurrence. — Common resident in Canadian and Hudsonian zones on both slopes of 

 Sierra Nevada. Eecorded from Merced Grove Big Trees and Chinquapin eastward to 

 Mono Lake Post Office and Walker Lake. Present in Yosemite Valley about foot of 

 Yosemite Falls. Lives in wet meadows and canon bottoms close to water. Nocturnal. 



Besides the meadow mice and shrews in the high mountain meadows 

 there is present, amid the same surroundings, another mammal not familiar 

 to many people, namely, the Jumping Mouse. In general form of body and 



