PEROMYSCUS. 199 
Geogr. Distr. State of Sonora, Mexico; extent of range unknown. 
Genl. Char. Similar in color to P. eremicus; soles bare; ears 
naked; tail long and scantily haired. 
Color. Above pale yellowish gray mixed with black; cheeks, 
outer side of arms, and sides pale fulvous or cinnamon; under 
parts white with buff spot on chest; hands and feet white; tail above 
little darker than back, beneath paler. 
Measurements. Total length, 217; tail vertebra, 113; hind foot, 23. 
167. hemionotis (Peromyscus), Elliot, Pub. Field Columb. Mus., 11, 
1903, p. 157. Zodlogy. 
MULE-EARED MOUSE. 
Type locality. Rosarito Divide, San Pedro Martir Mountains, 
Lower California, Mexico. 
Genl. Char. Similar in color to P. stephensi; ears enormous; tail 
very long. 
Color. Nose and tufts in front of ears dark gray; top of head 
and upper parts cream buff finely lined with black; bright ochraceous 
lateral line from lips to root of tail; under parts pure white, base of 
hairs plumbeous showing through; hands and feet white; tail above 
brownish black, beneath white; ears dark brown. 
Measurements. Total length, 222; tail vertebra, 126; hind foot, 
22.5; ear, 25.5. Skull: occipito-nasal length, 27; Hensel, 20.3; zygo- 
matic width, 13; interorbital constriction, 4.5; breadth of braincase, 
13; palatal arch to alveoli of incisors, 10.5; length of nasals, 10; 
greatest breadth of rostrum, 4; length of upper tooth row, 4; length 
of mandible, angle to alveolus of incisors, 11. 
168. gaurus (Peromyscus), Elliot, Pub. Field Columb. Mus., 11, 
1903, p.157. Zodlogy. 
Frisky Mouse. 
Type locality. San Antonio, San Pedro Martir Mountains, Lower 
California, Mexico. 
Genl. Char. Size large, tail very long, colors pale. Skull with 
broad braincase; nasals long; interorbital space broad. 
Color. Above ochraceous buff, finely lined with black; deepest 
and brightest on lower back and rump, becoming grayish cream buff; 
lined with black on upper back and top of head and nose, cheeks, 
sides, thighs, and upper parts of arms, legs, and entire under parts 
pure white, the plumbeous under fur showing through; hands and 
feet white; tail above dark wood brown, beneath cream color; ears 
blackish brown. 
Measurements. Total length, 222; tail vertebre, 122; hind foot, 
22; ear, 20. Skull: occipito-nasal length, 27; Hensel. 21; zygomatic 
