116 Bailey North American Species of Sigmodon. 

 Sigmodon alticola sp. nov. 



Type from Cerro San Felipe, Oaxaca, Mexico, at 10,000 feet altitude, 

 No. 68,231, U. 8. National Museum, Biological Survey Collection, $ ad. 

 Collected August 24, 1894, by E. W. Nelson and E. A. Goldman. 

 Orginal No. 6624. 



General characters. Size medium; tail hairy; pelage long and soft 

 both in winter and summer; colors dark and rich except gray ears. 



Color. Upperparts dark ochraceous or light umber brown; ears clear 

 gray, a little darker than in leucotis; belly pale cinnamon brown; feet 

 yellowish gray; tail black, becoming yellowish brown below at base. 



Skutt. Similar to that of leucotis in form but slenderer, less heavily 

 ridged and narrower interorbitally; interparietal narrow with a dividing 

 suture in middle; supraoccipital without median ridge; nasals narrow 

 -and rounded at ends; lateral pits of palate very shallow. 



Measurements. Type: total length 230; tail 101; hind foot 28.5. Skutt 

 of type: basal length 28.5; nasals 11; zygomatic breadth 17.8; mastoid 

 breadth 13.5; alveolar length of upper molar series 6.3. 



Distribution. Mountains of Oaxaca. 



Specimens examined. Cerro San Felipe 1, 15 miles west of Oaxaca 2. 



Sigmodon alticola amoles subsp. nov. 



Type from Final de Amoles, Queretaro, Mexico, at 7,000 feet altitude. 

 No. 81,430, U. S. National Museum, Biological Survey Collection, $ ad. 

 Collected September 18, 1898, by E. W. Nelson and E. A. Goldman. 

 Original No. 10,161. 



General characters. Similar to alticola but upperparts duller and less 

 tawny, skull wider interorbitally, with slightly smaller bullae and deeper 

 lateral pits of palate; interparietal narrower but not divided. 



Measurements. Type: total length 252; tail 105; hind foot 29.5. Skutt 

 of type: basal length 29.5; nasals 5.7; zygomatic breadth 19.6; mastoid 

 breadth 14; alveolar length of upper molar series 6.3. 



Distribution. Known from only 2 specimens from type locality. 



Remarks. While there seems hardly a possibility of continuity of 

 range across the wide gaps of low country separating the type localities 

 of the two forms, the slight difference of the present form from alticola 

 does not admit of more than subspecific rank. 



