156 CYNOMYS. 
Color. Summer Pelage. Above reddish brown, varied with gray 
and black hairs; beneath yellowish white; tail like the back with 
the apical third black. 
Winter Pelage. Above pale vinaceous buff, grizzled and mixed 
with black; below pale buff. 
Measurements. Total length, 393; tail vertebre, 88; hind foot, 
57. Skull: occipito-nasal length, 65; Hensel, 55; zygomatic width, 
47; interorbital constriction, 15; palatal length, 33; length of nasals, 
23; length of upper molar series, 17. 
116. gunnisoni (Cynomys), Baird, Proc. Acad. Nat. Scien. Phil., 
1855, p. 334. Elliot, Syn. N. Am. Mamm., 1901, p. 103. 
GUNNISON’S PRAIRIE-DOG. 
Type locality. Cochetopa Pass, Rocky Mountains, Saguache 
County, Colorado. 
Geogr. Distr. San Diego, State of Chihuahua, Mexico, into New 
Mexico and Arizona to Colorado. 
Genl. Char. Smaller than C. ludovicianus; tail one-sixth length 
of body. 
Color. Summer Pelage. Above tawny fulvous, mixed with 
black; under parts pale fulvous; tail like back on basal half, rest 
mixed black and white bordered and tipped with white. 
Winter Pelage. Above pale buff, mixed with black; under parts 
pale yellow to fulvous. 
Measurements. Average total length, 360; tail vertebrae, 69; 
hind foot, 60. Skull: occipito-nasal length, 57.5; Hensel, 28; zygoma- 
tic width, 41; interorbital constriction, 11.5; palatal length, 28.5; 
length of nasals, 20; length of upper molar series, 14. 
117. mexicanus (Cynomys), Merr., Proc. Biol. Soc. Wash., vu, 1892, 
P- 157- 
MEXICAN PRAIRIE-DOG. 
Type locality. La Ventura, State of Coahuila, Mexico. 
Geogr. Distr. Eastern and northern Mexico. 
Genl. Char. Sizelarge. Similar to C. ludovictanus, tail longer and 
blacker; nasals as long as distance from anterior edge of foramen 
magnum to posterior edge of palate. 
Color. Above grizzled buffy fulvous mixed with long black 
hairs; under parts, hands, and feet buffy; tail, basal half above like 
back, bordered with black, remainder black, beneath basal half buffy, 
remainder black and buff grizzled. 
Measurements. Totallength, 419; tail vertebre, 107; hind foot, 63. 
