356 PEROGNATHUS. 
Genl. Char. Similar to P. bimaculatus, but smaller; tail more 
hairy; lower premolar more nearly quadrate; audital bulle more 
separated. 
Color. Above pale ochraceous drab, lined with black; ears and 
spot at base of whiskers blackish; orbital area pale buff; spot behind 
eye and also the lateral line on body pale buff; feet and under parts 
white; tail hoary at base, tip dusky. 
Measurements. Total length, 109; tail vertebrz, 53; hind foot, 
15.5; ear from crown, 4.7. Skull: length of Hensel, 13; occipito- 
nasal length, 19; greatest mastoid breadth, 11; length of inter- 
parietal, 2.2; greatest width of interparietal, 3.4; interorbital con- 
striction, 4.9; length of nasals, 7. 
apache melanotis (Perognathus), Osgood, N. Am. Faun., No. 18, 1900, 
9s Die 
BLACK-EARED Pocket MOUSE. 
Type locality. Casas Grandes, State of Chihuahua, Mexico. 
Geogr. Distr. Known only from type locality. 
Genl. Char. Similar to P. apache, but darker, smaller. 
Color. Above rich buff, lined with black; under parts pure 
white; orbital region buff; ears, edges, and spot at base white; inside 
black; tail above dusky, beneath buffy white. 
Measurements. Total length, 133; tail vertebre, 65; hind foot, 
19.5. - Skull: length of Hensel, 15.3; occipito-nasal lengthy. 
greatest mastoid width, 11.8; length of interparietal, 2.8; greatest 
interparietal width, 4.3; interorbital constriction, 5; length of 
nasals, 8. 
B. Chetodipus. 
‘‘Mastoids moderately developed, not projecting behind plane 
of occiput; interparietal broadly pentagonal, or strap-shaped; mas- 
FiG. 68. PEROGNATHUS (CHATODIPUS) FEMORALIS MESOPOLIUS. 
No. 10374 Field Columbian Mus. Nat. size. 
Tooth rows enlarged g times. 
