2:*0 SIGMODON. 



202. minimus (Sigmodon}, Mearns, Proc. U. S. Nat. Mus., xvn, 



1894, p. 130. Elliot, Syn. N. Am. Mamtn., 1901, p. 146. 

 LEAST COTTON RAT. 



Type locality. Northern boundary line between New Mexico 

 and Mexico, 100 miles west of the Initial Monument in Grant County, 

 on the west bank of the Rio Grande. 



Geogr. Distr. Northern Mexico and southern New Mexico and 

 Arizona. 



Genl. Char. Darker in color and hair more bristly than 5. h. 

 texcnsis; ears, feet, and tail thickly covered with hair; tail indis- 

 tinctly bicolor. 



Color. Above mixed brown, gray, and black; beneath pale buff; 

 tail brownish black; feet yellowish gray. 



Measurements. Total length, 223; tail, 94; hind foot, 28; ear 

 above crown, 14. Skull of type: basal length, 28.5; nasals, 11.3; 

 zygomatic breadth, 19; mastoid breadth, 14; alveolar length of upper 

 molar series, 5.9. 



203. leucotis (Sigmodon), Bailey, Proc. Biol. Soc. Wash., xv, 1902, 



p. 115. 

 WHITE-EARED COTTON RAT. 



Type locality. Valparaiso Mountains, State of Zacatecas, Mexico. 

 Altitude, 8,700 feet. 



Geogr. Distr. Known only from the type locality. 



Genl. Char. Size medium; tail short, hairy. Skull heavily ridged 

 along sides; interparietal narrow with a median suture; no median 

 ridge on supraoccipital ; nasals short; bullae oval. 



Color. Above dull brownish gray; under parts whitish; hands 

 and feet brownish gray; tail black, brownish at base beneath; ears 

 whitish gray. 



Measurements. Average of 8 adult topotypes: total length, 234; 

 tail vertebrae, 91; hind foot, 29.4. Skull of type: basal length, 31; 

 nasals, 11.4; zygomatic breadth, 20.5; mastoid width, 15; alveolar 

 length of upper molar series, 6. (Bailey, 1. c.) 



204. ochrognathus (Sigmodon), Bailey, Proc. Biol. Soc. Wash., xv, 



1902, p. 115. 



OCHRACEOUS-FACED COTTON RAT. 



Type locality. Chisos Mountains, Brewster County, Texas. Alti- 

 tude, 8,000 feet. 



Geogr. Distr. Chisos Mountains, Texas, to Parral, State of 

 Chihuahua, Mexico. 



Genl. Char. Size small; tail long, hairy. Skull: interparietal with 

 a posterior indentation; nasals short, wide, and truncate posteriorly. 



