a 
PERODIPUS. 351 
interorbital constriction, 13; length of nasals, 13.5; mastoid width, 
23; length of upper molar series, 5; length of mandible, 18.3. 
357. obscurus (Perodipus), Allen, Bull. Am. Mus. Nat. Hist., 1yo3, 
p. 603. 
Dusky KancGaroo Rat. 
Type locality. Rio Sestin, State of Durango, Mexico. 
Genl. Char. Color very dark; size moderate. 
Color. Dorsal area gray brown suffused with fulvous; flanks 
more fulvous; lower half of cheeks, sides of neck, small spot above 
eye, postauricular patch, band on thighs, fore legs, inner side of 
hind legs and entire under parts white; tip of nose and bar at base 
of whiskers black; ear buffy white; tail with dorsal and ventral 
stripes blackish; sides and basal ring white. 
Measurements. Total length, 232; tail vertebre, 130; hind foot, 
35; ear from notch, 12.7. Skull: total length, 36; greatest mastoid 
breadth, 23; length of nasals, 13. 
358. agilis (Dipodomys), Gambel, Proc. Acad. Nat. Scien. Phil., 
1848, p. 77. Elliot, Syn. N. Am. Mamm., rgo1, p. 236. 
hermannt & wagneri Le Conte, Proc. Acad. Nat. Scien. Phil., 1848, 
P- 77- 
NIMBLE KANGAROO Rat. 
Type locality. Los Angeles, Los Angeles County, California. 
Geogr. Distr. lower California, Mexico to southern and middle 
California. 
Genl. Char. Size small; color dark; body rather stout. 
Color. Above ashy brown, heavily lined with black, especially 
on top and sides of head and lower back; sides yellowish brown; 
spot over eye and behind ear, side of snout, stripe on thighs and 
under parts white; facial crescent black and broad, and meeting on 
bridge of nose; tail blackish and with a blackish tip, lateral white 
stripes terminating at base of pencil; under part of leg and base of 
foot dusky; rest white. 
Measurements. Total length, 280; tail vertebre, 170; hind leg, 
39.5; ear, 14.5. Skull: total length, 38; Hensel, 24; zygomatic 
width, 17.5; interorbital constriction, 12; mastoid breadth, 24; 
palatal length to incisive foramina, 7; median length of nasals, 7.5; 
length of upper molar series, 3.5; length of mandible, condyle to tips 
of incisors, 20. 
