124 Merriam — New Mice from Mexico and Guatemala. 



Crania! characters. — Skull resembling that of P. gratus, but larger, brain- 

 case flatter ; zygomata more spreading and less notched by anteorbital 

 slit; rostrum heavier as seen from below; audita! bullae smaller; nasals 

 longer. 



Measurements. — Type specimen: Total length 200; tail vertebrae 102; 

 hind foot 23.5. 



Peromyscus hylocetes sp. nov. 



Type from Patzcuaro, Miehoacan, Mexico (alt. about 8000 ft.). No. 

 50423, $ ad., U. S.Nat. Mus., Biological Survey Coll. Collected July 

 27, 1892, by E. W. Nelson and E. A. Goldman. Orig. No. 2901. 



Character*. — Size medium ; ears medium; tail shorter than head and 

 body well haired and sharply bicolor. Color grayish. 



Color. — Upperparts huffy gray becoming huffy ochraceous on sides and 

 with a broad dark dorsal area resulting from bountiful admixture of black 

 hairs ; underparts, lips, and fore feet whitish ; wrists and ankles dusky, 

 the color of latter spreading over basal part of hind foot; tail dusky 

 above, white below. 



Cranial characters. — Skull rather broad,, and short, with moderately 

 spreading zygomata and no supraorbital beads : braincase rather full and 

 broadly rounded ; audita! bullae smaller than in the truei-difficilis group, 

 but larger than in mexicanus and slightly larger than oaxacensis. 



Measurements. — Type specimen: Total length 238; tail vertebra? 114; 

 hind foot 25. Average of 3 specimens from type locality : Total length 

 232; tail vertebrae 112; hind foot 26 



Peromyscus musculoides sp. nov. 



Type from Cuicatlan, Oaxaca, Mexico (alt. 1800 ft.). No. 69661, cf old, 

 U. S. Nat. Mus., Biological Survey Coll. Collected Oct. 14, 1894, by E. W. 

 Nelson and E. A. Goldman. Orig. No. 6892. 



Characters. — Size a little larger than Mas musculus, which it greatly re- 

 sembles; pelage short, close and rather coarse; ears rather short; tail 

 shorter than head and body, moderately haired, bicolor. 



Color.— Upperparts drab gray, becoming brownish on sides ; underparts, 

 lips and sides of nose milk-white; ankles dusky; fore and hind feet 

 white; tail brownish above, whitish below. 



Cranial characters. — Skull small ; braincase rounded ; frontals broad be- 

 tween orbits but without trace of ' bead ' ; zygomata strongly notched by 

 anteorbital slits ; audital bullae small. 



Measurements.— Type specimen: Total length 187; tail vertebrae 88; 

 hind foot 22.5. Average of 10 specimens from type locality : Total length 

 185; tail vertebras 84.5 ; hind foot 22.5. 



Peromyscus mekisturus sp. nov. 



Type from Chalchicomula, Puebla, Mexico (alt. 8400 ft.). No. 64108, 

 $ ad., U. S. Nat. Mus., Biological Survey Coll. Collected March 16, 

 1894, by E. W. Nelson and E. A. Goldman. Orig. No. 5951. 



