SIGMODON. 227 
Measurements. Total length, 198; tail, go; hind foot, 25; ear 
from notch, 18. Skull: total length, 31.5; Hensel, 27.3; length of 
nasals, 12.5; zygomatic width, 18.3; mastoid width, 13.3; alveolar 
length of upper molar series, 5.6. 
hispidus mascotensis. 
mascotensis (Sigmodon), Allen, Bull. Amer. Mus. Nat. Hist., 
1897, Pp. 54. 
come Allen, Bull. Am. Mus. Nat. Hist., 1897, p. 55. 
Mascota Cotton Rat. 
Type locality. Mineral San Sebastian, Mascota, State of Jalisco, 
Mexico. 
Geogr. Distr. Western portion of State of Jalisco to southern 
part of State of Oaxaca, Mexico. 
Genl. Char. Larger than S. h. berlandiert, tail longer, hind foot, 
larger. 
Color. Above cinnamon brown; sides paler; belly white; hands 
and feet yellowish gray; tail above dark brown, sides and beneath 
paler. 
Measurements. Total length, 272; tail vertebre, 117; hind foot, 
32. Skull: total length, 34.5; basal length, 30.4; zygomatic breadth, 
19.5; mastoid breadth, 13.2; interorbital constriction, 4.8; length of 
nasals, 13.5; length of upper molar series, 6.7. 
hispiduws eremicus (Sigmodon), Mearns, Proc. U. S. Nat. Mus., 
1897, Pp. 504. 
WESTERN DeEsERT Cotton Rat. 
Type locality. Cienega Well, Colorado River, State of Sonora, 
Mexico, thirty miles south of Monument No. 204, Mexican boun- 
dary line. 
Geogr. Distr. Western Desert Tract, Lower Colorado River, 
State of Sonora, Mexico. 
Genl. Char. Nasals spatulate at extremity; coloring yellowish 
instead of grayish. 
Color. Yellowish gray, the sides and rump tinged with ochra- 
ceous; under surface white; feet grayish white; tail inclined to black- 
ish above. 
Measurements. Total length, 280; tail vertebre, 128; hind foot, 
34; ear, 15. Skull: basal length, 30.6; zygomatic breadth, 20.3; 
mastoid breadth, 14; length of nasals, 13.3; length of upper molar 
series, 6.6. 
hispidus berlandieri. 
berlandiert (Sigmodon), Baird, Proc. Acad. Nat. Scien. Phila., vit, 
1355, Da.333: 
