192 PEROMYSCUS. 
BLACK-TAILED MOUSE. 
Fype locality. Hacienda La Parada, State of San Luis Potosi, 
Mexico. 
Geogr. Distr. Middle portion of tableland in States of San Luis 
Potosi, Zacatecas and Nuevo Leon. 
Genl. Char. Similar to P. eremicus, but darker; tail unicolor. 
Color. Shades of buff deeper than in P. eremicus and upper 
parts more heavily mixed with black; under parts white; tail blackish 
brown above and below; hands and feet white; ankles dusky. 
Measurements. Total length, 176-195; tail vertebre, 92-103; hind 
FOOL 21: 
attwateri pectoralis (Peromyscus), Osgood, Proc. Biol. Soc. Wash., 
KV LOCA DP 50: 
JALPAN MOUSE. 
Type locality. Jalpan, State of Queretaro, Mexico. 
Genl. Char. Similar to P. attwatert; pectoral spot prominent. 
Color. Upper parts pale ochraceous buff thickly sprinkled with 
dusky; sides of head behind eyes grayish; a narrow black orbital 
ring; pectoral spot buffy ochraceous; under parts white; tail above 
dusky, beneath white; hands and feet white. 
Measurements. Total length, 200; tail vertebre, 114; hind foot, 
22. Skull: greatest length, 27; Hensel, 19.7; zygomatic width, 13.7; 
interorbital constriction, 4.2; length of nasals, 9.9; palatal length, 
3.7; palatine foramina, 4.9X2; postpalatal length, 9.4; length of 
upper molar series, 3.8. 
attwateri eremicoides (Peromyscus), Osgood, Proc. Biol. Soc. Wash., 
XVII, 1904, p. 60. 
ALLIED MOUSE. 
Type locality. Mapimi, State of Durango, Mexico. 
Genl. Char. Similar to P. eremicus, but molar enamel pattern 
having accessory cusps. 
Color. Upper parts mixed pinkish buff and dusky; lateral line 
pinkish buff; facial region grayish; under parts pale creamy white; 
tail above dusky, beneath white; hands, feet, and ankles white. 
Measurements. Total length, 180-195; tail vertebre, 102-111; 
hind foot, 20-21. Skull: greatest length, 24; Hensel, 18; zygomatic 
width, 12; interorbital constriction, 3.9; interparietal, 8.33; length 
of nasals, 8.5; palate, 3.5; palatine foramina, 4.51.5; postpalatal 
length, 8.5; length of upper molar series, 3.5. 
154. metallicola Elliot, Pub. Field Columb. Mus., 111, 1903, p. 245. 
Zoology. 
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