180 PEROMYSCUS. 
Genl. Char. Similar to P. spicilegus; dusky area on hind foot 
from ankle to base of toes. Skull heavier; teeth larger. 
Color. Upper parts tawny mixed with dusky; orbital ring and 
base of whiskers black; pectoral spot tawny; under parts creamy 
white; tail above blackish, below white; forearm sooty to wrist; 
hands white; ankle and proximal half of foot above sooty. 
Measurements. Average of five adults: Total length, 211; tail 
vertebre, 106; hind foot, 25. Skull: greatest length, 29; Hensel, 
22; zygomatic width, 14.4; interorbital constriction, 4.6; interparietal 
9.33.2; length of nasals, 11.5; palate, 4.7; postpalatal length, 9.1; 
length of upper molar series, 5. 
b.—simulus (Peromyscus), Osgood, Proc. Biol. Soc. Wash., xvil, 
1904, p. 64. 
Mimic Mouse. 
Type locality. San Blas, Territorio de Tepic, Mexico. 
Genl. Char. Similar to P. spicilegus. Skull smaller; nasals shorter. 
Color. Upper parts cinnamon rufous; dorsal area darker; under 
parts white; pectoral spot rufous; tail bicolor; hands and feet white; 
ankles dusky. 
Measurements. Average of three adults: Total length, 208; tail 
vertebrz, 111; hind foot, 23. Skull: greatest length, 26.3; Hensel, 
20.3; zygomatic width, 14; interorbital constriction, 4.1; length of 
nasals, 9.4; palate, 3.6; postpalatal length, 9.4; length of upper 
molar series, 3.8. 
135. affinis (Hesperomys), Allen, Proc. U.S. Nat. Mus., 1891, p. 195. 
ALLIED FiELD Mouse. 
Type locality. Barrio, State of Oaxaca, Mexico. 
Geogr. Distr. Southeastern Mexico. 
Genl. Char. Similar to P. melanophrys, but darker. 
Color. Above mixed fulvous brown and black, dorsal area dark- 
est; flanks fulvous; under parts white tinged with yellow; ears 
brownish with white edges; hands and feet white; tail above brown, 
beneath paler. 
Measurements. Total length, 157-171; tail vertebre, 76-83; 
hind foot, 19.8; ear, 4.5. Skull: total length, 26.4; basal length, 25.9; 
length of nasals, 11.4; length of mandible, 16; height at angle, 6.4. 
(ex. Type.) 
a.—museuloides (Peromyscus), Merr., Proc. Biol. Soc. Wash., x1, 
1898, p. 124. 
ALLIED House Mouse. 
Type locality. Cuicatlan, State of Oaxaca, Mexico. 
