MAMMALS OF THE MEXICAN BOUNDARY. 369 



KEY TO EIGHT SPECIES A.ND SI BSPECIES OF ONYI HOMYS. 



a. Size large. Length, more than L50 mm; total Length of skull, aboul 30 mm. 

 b. Size largest. Length, aboul 170 nun; tail vertebrae, 57; bind foot,24. Colorabove, 



mouse-gray .Onyckomys longipi s ' p. 369 



bb. Size smaller. Length, about 160 mm; tail vertebrae, 50; hind foot, 22. 

 c. Coloration very pale. Color above, pale tawny-cinnamon. 



Onychomys pallescens (p. 371). 

 cc. Coloration dark. 



</. Color above, blackish slate (extralimital i Onychomys fuliginosus. 



,1(1. Color above, tawny-cinnamon Onychomys mdanophrys (p. 372 . 



aa. Size small. Length, less than 150 nun; total Length of skull, aboul 25.5 mm. 

 i . Coloration dark. 



/'. Color above, taw ny-einnamon .Onychomys torridus ( [>. 374 I. 



ff. Color above, dark-grayish drab or mouse-gray. 



Onychomys torridus ranvona (p. 379 

 ee. Coloration very pale. 



g. Size smallest. Length, about 137 nun; tail vertebras, 53; ear from 

 crown, 14; hind foot, 21. Skull, 25.5 by 13..") nun. Color above, pale 



grayish drab Onychomys torridus arenicola (p. 377). 



gg. Larger. Length, about 154 mm; tail vertebrae, 56; ear above crown, 

 15; hind foot, 21.5. Skull, 25.5 by 13.5 mm. Color above, pale drab- 

 gray Onychomys torridus />i r pallid us (p. 378). 



ONYCHOMYS LONGIPES Merriam. 

 TEXAS GRASSHOPPER MOUSE. 



Onychomys longipesM.EBS.iAM, North American Fauna, No. 2, Oct. 30, 1889, pp. !. 2, 1. 



and 5 (original description). — Miller and Reiix, Proc. I5ost. Soc. Nat. Hist., 



XXX, No. 1, Dec. 27, 1901, p. 00 (Syst. Results Study X. Am. Mam. tocloseof 



1900). 

 [Onychomys leucogaster]2ongipes, Elliot, Field Col. Mus., Zool. Ser., 11, 1901, p. 120 



(Synop. Mam. X. Am.). 



Type-locality. — Concho County, Texas. (Type, skin and skull. No. 

 llfih collection of Dr. C. Hart Merriam.) 



Geographical range. — Texas. Inhabits the Sonoran Zone from the 

 Gulf of Mexico west to Kinney County (Fort (lark) and north to 

 Fort Sill, Indian Territory (Dr. J. C. Merrill). 



Description. — Size, large (about the same as 0. melanophrys) . 

 Length, 170 mm.; tail vertebrae, 57 (to end of pencil, 61); ear, above 

 crown, 14.5; ear above notch, 18; length of hind foot, 23.5. Skull. 

 30 by 15.5; Coloration, dark; above, grayish drab, tingedwith cinna- 

 mon and mixed with black in the form of fine annotations and points 

 to the hairs, and with a narrow stripe of dull cinnamon along each 

 side, between the drab of the back and the while of the belly. Under 

 parts, feet, tip, and under side of (ail, white. Ears dusky, with a 

 mixture of hoary at the tips, a black spot on the anterior border of 

 their outer surface, and with the woolly tuft at base, which is 

 30639 No. 56—07 m 24 



