348 DIPODOMYS. 
feet white; tail with a bushy pencil, the upper parts to tip pale drab, 
sides and beneath white; ears naked, yellowish. 
Measurements. Type. Total length, 225; tail vertebra, 134; 
hind foot, 36; ear, 15. Average of ten specimens: Total length, 
234.7; tail, 137.3; hind foot, 36.7; ear, 14.1. Skull: total length, 
posterior line of mastoids to anterior end of nasals, 34; Hensel, 20; 
zygomatic width, 15; width of mastoids, 22; greatest width of parietal, 
15; length of nasals, 12; greatest width of rostrum, 5; palatal length, 
t1; length of upper tooth row, 3; length of mandible, condyle to tip 
of incisors, 16; length of lower tooth row, 3. 
e.—atronasus (Dipodomys), Merr., Proc. Biol. Soc. Wash., 1x, 1894, 
Petts. 
BLACK-NOSED KANGAROO Rat. 
Type locality. Hacienda La Parada, 25 miles northwest of the 
City of San Luis Potosi, State of San Luis Potosi, Mexico. 
Geogr. Distr. Known only from type locality, Mexico. 
Genl. Char. Similar to D. merriami1, but darker. 
Color. Above dark clay color; sides ochraceous buffy; nose from 
tip to eyes blackish; usual black stripes on face and thighs; tail 
black above and below, white on sides to middle third of the length. 
Measurements Total length, 267; tail vertebra, 162; hind foot, 
40. 
f.—melanurus (Dipodomys), Merr., Proc. Calif. Acad. Scien., 2d 
Ser., 1893, p. 345. 
BLACK-TAILED KANGAROO Rat. 
Type locality. San Jose del Cabo, Lower California, Mexico. 
Geogr. Distr. Cape region of Lower California, Mexico. 
Genl. Char. Like D. merriamtz; terminal third of the tail blackish. 
Color. Above mixed pale ochraceous buff and black; face and 
supra-orbital spot white; under parts white; penicillate part of tail 
blackish, rest like D. merriamt. 
Measurements. Total length, 240; tail vertebre, 141; hind foot, 
36.5. 
The description given of the Kangaroo Rats of the genus Dipod- 
omys will answer perfectly for the members of PERopipus. They 
closely resemble each other in general appearance, and the presence 
of a fifth toe on the hind foot was not suspected, so minute is it, for 
a considerable time after the animals were known to naturalists. 
