378 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Measurements of type of Omjehonn/s fnrridus arenicola. 



ONYCHOMYS TORRIDUS PERPALLIDUS Mearns. 

 YUMA GRASSHOPPER MOUSE. 



Onychomy.t torridus perpallidvs Mearns, Proc. U. S. Nat. Mus., XIX, 1890, p. 140 (p. 4 

 of advance .sheet issued May 25, 1896; original de.scription). — Miller and Reiin, 

 Proc. Bost. See. Nat. Hist., XXX, No. 1, Dec. 27, 1901, p. (i7 (Syst. Results Study 

 N. Am. Mammals to close of 1900). 



[Onychomys iorridus] per[)aUidu.<s. Elliot, Field Col. Mus.,Zn<)l. Scr., II, 1901, p. 122 

 (Synop. Mam. X. Am.). 



O[nychomy.s] t[orridii.<i] perpallidvs^ Elliot, Field Col. jMus.,Zoo1. Ser., IV, 11K)4, pp. 

 I(i5, 168 (Mam. Mid. Aul). 



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

 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. 06.— Onychomy.s TORRiDtTs PEEP.'VLLIDVS. Skull OF TYPE, a, Dors.\l view; 6, Ventr.^l view; 



c, Later.vl 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 less 

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

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



