PEROMYSCUS. 201 
WHITE-TAILED MOUSE. 
Type locality. Tehuantepec, Mexico. 
Geogr. Distr. Southern Mexico. 
Genl. Char. Size about that of P. caltfornicus; ears large; tail 
long, distal half white. 
Color. Above cinereous gray lined with black; under parts white; 
hands and feet white; tail, proximal half brown, distal half white; 
ears blackish brown. 
Measurements. Total length, 260; tail, 142; hind foot, 25.5; ear 
from notch, 17.5. Skull: greatest length, 30.3; greatest breadth, 15; 
length of nasals, 11.2; breadth of nasals, 3.4; interorbital constriction, 
5.1; interparietal breadth, 10; interparietal length, 3.9; palatal length, 
11.9; length of upper molar series, 4.5; length of mandible, condyle 
to tip of incisor, 18.2; height of coronoid process, 7.4. 
a.—sadovi (Peromyscus), Thomas, Ann. Mag. Nat. Hist., 7th Ser., 
XI, 1903, p. 484. 
Gapow’'s Mouse. 
Type locality. San Carlos, Yautepec, State of Oaxaca, Mexico. 
Altitude, 2,250 feet. 
Genl. Char. Similar to P. leucurus, color darker, ears larger. 
Color. Upper parts pale brown tinged with buff; sides like back; 
under parts soiled grayish; chin white; hands and feet white; tail 
black above and at tip, beneath white. 
Measurements. Total length, 265; tail, 150; hind foot, 27.6; ear, 
25. Skull: greatest length, 31.5; basilar length, 24; zygomatic 
breadth, 4.2; breadth of braincase, 14; interparietal, 4.2X11.5; 
palatal length, 12.5; palatal foramina, 6.62.6; length of upper 
molar series, 4.7. 
172. melanophrys (Hesperomys), Coues, Proc. Acad. Nat. Scien. 
Phil., 1874, p. 181. 
BLACK-BROWED MOousE. 
Type locality. Santa Efigenia, Tehuantepec, State of Oaxaca, 
Mexico. 
Geogr. Distr. Southern Mexico, Tehuacan and Tehuantepec, 
States of Puebla and Oaxaca. 
Genl. Char. Size large; tail longer than head and body; ears 
large. Skull: palate ending opposite last molars. 
Color. Above gray, tinged with fulvous, darker on dorsal line; 
sides fulvous; head gray; orbital ring black; under parts pure white; 
hairs at base plumbeous; hands and feet white; tail above like the 
back, beneath gray. 
Measurements. Total length, 245; tail vertebre, 135; hind foot, 
