230 SIGMODON. 
202. minimus (Sigmodon), Mearns, Proc. U. S. Nat. Mus., xvit, 
1894, p. 130. Elliot, Syn. N. Am. Mamm., 1901, p. 146. 
Least Cotton Rat. 
Type locality. Northern boundary line between New Mexico 
and Mexico, roo 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 S. h. 
texensis; 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, 
Pe I15, 
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; bulle 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 vertebre, 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, 
1GO2), ep. lL 5: 
OCHRACEOUS-FACED CoTTon Rat. 
Type locality. Chisos Mountains, Brewster County, Texas. Alti- 
tude, 8,o00 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. 
