72 The Mammals of Colorado 
i., |; pm., {; m., | X 2 =20; incisors narrow, clearly marked with 
a median groove; molars simple, transversely elongated without 
reentrant angles. 
All the species have certain markings in common, as follows; 
more or less distinct crescentic black facial lines; side of mouth, 
spot over eyes and behind ear, white; and a white stripe across 
thigh usually reaching the tail. 
FIG. 26. MOKI KANGAROO RAT, PcTodlpliS longipes 
Skull, showing dentition, x 2^ 
This genus contains the five-toed Kangaroo Rats and 
ranges over the western half of the United States from Oregon 
and Nebraska southwards into Mexico as far as the State 
of San Luis Potosi. 
Elhot gives a fist of 16 described species in his Check-list; 
of these three have been met with in the State of Colorado. 
Key to Species of Perodipus 
A. Color pure, bright buffy. P. longipes, a, p. 77. 
B. Color dusky. P. longipes, b,i p. 77. 
1 This is a dark form of longipes found in southwestern Montrose 
County. 
