156 CYNOMYS. 



Color. Slimmer 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 vertebrae, 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., vn, 1892, 



P- 157- 

 MEXICAN PRAIRIE-DOG. 



Type locality. La Ventura, State of Coahuila, Mexico. 



Geogr. Distr. Eastern and northern Mexico. 



Genl. Char. Size large. Similar to C ' . ludovicianus, 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. Total length, 419 ; tail vertebrae, 107 ; hind foot, 63. 



