378 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Measurt ments-qf type of Onychomys torridus art nicola. 



ONYCHOMYS TORRIDUS PERPALLIDUS Mearns. 

 YUMA GRASSHOPPER MOUSE. 



Onychomys iorridus perpaUidus Mearns, Proc. U. S. Nat: Mus., XIX, 1896, p. 140 (p. 4 

 of advance sheet issued May 25, 1896; original description) . — Miller and Rehn, 

 Proc. Bost. Soc. Nat. Hist.. XXX, No. I. Dec. 27, 1901, p. 67 (Syst. Results Study 

 \. Am. Mammals to dose of 1900). 



[Onychomys torridus] perpaUidus, Elliot, Field Col. Mus.,Zool. Sec. II, 1901, p. 122 

 (Synop. Maui. X. Ami.). ■ 



0[nychomys] t[orridus] perpaUidus, Elliot, Field Col. Mus.,Zool. Ser., IV. 1 ( .M)4, pp. 

 165, 168 (Mam. Mid. Am.). 



Type-locality. —Left (east) bank of the Colorado River, at Monu- 

 ment No. 204. (Type, skin and skull, Cat. No. 60174, U. S. National 

 Museum.) 



Geographical range. — Lower Sonoran Zone of the Western Desert 

 Tract. 



Fig. 66. -Onychomys torridus perpallidus. Skull of type, o, Dorsal view; b, Ventral view; 



c, Lateral view. 



Description. Slightly larger than typical Onychomys torridus, with 

 relatively larger ears and longer tail, and a much paler coloration. 

 Color above drab-gray, becoming more cinereous anteriorly ; sides and 

 rump barely tinged with fawn color; dusky line on basal three- 

 fourths of upper side of tail much obscured by whitish hairs; ears leso 

 densely clothed than in the other subspecies of 0. torridus, and with- 

 out a well-defined dusky spot; whiskers mostly white or colorless; 



