191} PEROMYSCUS. 



BLACK-TAILED MOUSE. 



Type 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 vertebrae, 92-103 ; hind 

 foot, 21. 



attwateri pectoralis (Peromyscus] , Osgood, Proc. Biol. Soc. Wash., 



xvii, 1904, p. 59. 

 JALPAN MOUSE. 



Type locality. Jalpan, State of Queretaro, Mexico. 



Genl. Char. Similar to P. attwateri; 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 vertebras, 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 vertebrae, 102-111; 

 hind foot, 20-21. Skull: greatest length, 24; Hensel, 18; zygomatic 

 width, 12; interorbital constriction, 3.9; interparietal, 8.3X3; length 

 of nasals, 8.5; palate, 3.5; palatine foramina, 4.5x1.5; postpalatal 

 length, 8.5; length of upper molar series, 3.5. 



154. metallicola Elliot, Pub. Field Columb. Mus., in, 1903, p. 245. 

 Zoology. 



