New Mice from Mexico and Guatemala. 119 



Cranial and dental characters. Skull small and short (compared with 

 others of the series) ; braincase rather broadly rounded and flattened ; 

 zygomata weak and not strongly notched by anteorbital slit; audital 

 bullee small but slightly larger than in the decidedly larger P. mexicanus ; 

 molars slightly larger than in mexicanus and series of same length, though 

 narrower than, in the allied but very much farger P. guatemalenxix. 



Measurements. Type specimen: Total length 238; tail vertebrae 114; 

 hind foot 28. Average of 5 specimens from type locality: Total length 

 230; tail vertebrae 112; hind foot 27.3. 



Remarks. P. Upturns might easily be mistaken for the young of the 

 dark form of mexicanus (totontepecus] which also occurs on Mt. Zempoal- 

 tepec, but a glance at the skulls is sufficient to distinguish them, that of 

 P. lepturus* being hardly three- fourths as large -as totontepecus while its 

 molar teeth are even larger than those of totontepecus. 



Peromyscus megalops sp. nov. 



Type from Mts. near Ozolotepec, Oaxaca, Mexico. No. 71592, J^ old, 

 U. S. Nat. Mus., Biological Survey Coll. Collected March 26, 1895, by 

 E. W. Nelson and E. A. Goldman. Orig. No. 7733. 



Characters. Size rather large ; ears rather short; tail long and scantily 

 haired ; fur long and soft; coloration dark with a rich chestnut fulvous 

 suffusion. 



Color. Upperparts finely mixed black and dark fulvous, the black pre 

 dominating between ears and along back ; the salmon-fulvous predomi 

 nating on sides and cheeks ; underparts whitish, the plumbeous basalfur 

 showing through ; pectoral region salmon-fulvous ; wrists and ankles 

 dusky; fore feet whitish ; hind feet clouded. 



Cranial characters. Skull large and long, resembling that of guatema- 

 lensis in size and general characters but audital bullye decidedly smaller ; 

 incisive foramina much more widely open ; frontals conspicuously broader 

 and developing a distinct supraorbital bead. 



Measurements. Type specimen : Total length 282 ; tail vertebrae 150 ; 

 hind foot 31. Average of 5 specimens from type locality : Total length 

 278; tail vertebrae 147; hind foot 31. 



Peromyscus auritus sp. nov. 



Type from Mts. 15 miles west of Oaxaca, State of Oaxaca, Mexico. No. 

 68438, 9 old, U. S. Nat. Mus., Biological Survey Coll. Collected Sept. 

 17, 1894, by E. W. Nelson and E. A. Goldman. Orig. No. 6795. 



Characters. Similar to P. megalops, but ears and audital bullse very much 

 larger and coloration duller. Similar to' P. guatemalensis, but paler and 

 less fulvous, and frontal much narrower between orbits. 



Color. Upper parts grayish brown, becoming dusky on sides of nose, 

 around eyes, and on back, with a pale dull fulvous wash on cheeks and 

 sides; under parts whitish, the plumbeous basal fur showing through ; 

 wrists and ankles dusky; fore and hind feet whitish ; tail dusky above, 

 whitish beneath. 



