180 PEROMYSCUS. 



GcnL 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 

 vertebrae, 106; hind foot, 25. Skull: greatest length, 29; Hensel, 

 22; zygomatic width, 14.4; interorbital constriction, 4.6; interparietal 

 9.3X3.2; 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., xvii, 



1904, p. 64. 

 MIMIC MOUSE. 



Type locality. San Bias, 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 

 vertebras, in; 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 vertebrae, 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. musculoides (Peromyscus'), Merr., Proc. Biol. Soc. Wash., xn, 



1898, p. 124. 

 ALLIED HOUSE MOUSE. 



Type locality. Cuicatlan, State of Oaxaca, Mexico. 



