PEROMYSCUS. alieyut 
STEPHEN’S FieELD Mouse. 
Type locality. Canon at east base of Coast Range Mountains, in 
San Diego County, California, near Mexican boundary. 
Geogr. Distr. Southern California into Lower California, Mexico. 
Genl. Char. Similar to P. eremicus, but smaller, tail longer, and 
colors paler. 
Color. Above grayish cream buff; sides and rump pale ochra- 
ceous buff; feet and under parts white; tail above dusky, below white. 
Measurements. Total length, 193; tail vertebra, 108; hind foot, 
1g; ear, 18.5. Skull: occipito-nasal length, 24; Hensel, 18; zygo- 
matic width, 12; interorbital constriction, 3.5; palatal length, 9; 
length of upper molar series, 3. 
153. eremicus (Hesperomys), Baird, Mamm. N. Am., 1857, p. 479. 
eremicus (Peromyscus), Elliot, Syn. N. Am. Mamm., 1901, p. 136. 
Desert Mouse. 
Type locality. Old Fort Yuma, San Diego County, California. 
Geogr. Distr. Lower California and State of Sonora, Mexico, into 
New Mexico, Arizona, and California. 
Genl. Char. Ears very large; tail longer than head and body; 
palms and soles naked. 
Color. Above pale yellowish gray, mixed with black; pale ful- 
vous band on cheeks and sides; tail obscurely bicolor, above little 
darker than dorsal region; feet whitish. 
Measurements. Total length, 190; tail vertebra, 96.5; hind foot, 
22; ear, 19. Skull: occipito-nasal length, 26.5; Hensel, 19; zygo- 
matic width, 13; interorbital constriction, 4; palatal length, 10; 
length of nasals, 10; length of upper molar series, 3. 
a.—arenarius (Peromyscus), Mearns, Proc. U. S. Nat. Mus., 1896, 
Pease. lillior, syn. N), Am. Mamm., 1roor, p. 136: 
SAND-LOVING Mouse. 
Type locality. Rio Grande, near El Paso, El Paso County, 
Texas. 
Geogr. Distr. State of Chihuahua, Mexico, into southern Texas. 
Genl. Char. Similar to P. eremicus, without dark dorsal line. 
Color. Above and sides pale ochraceous drab mixed with black; 
tail above dusky drab and hoary, below pure white; head grayish; 
orbital ring dusky. 
Measurements. Total length, 198; tail vertebra, 106; hind foot, 
Sryg- ear, rs. 
b.—pheurus (Peromyscus), Osgood, Proc. Biol. Soc. Wash., xvi, 
1904, p. 75. 
