1916.] 



CYNOMYS GUNNISONI GUNNISONI. 



31 



54.8 (52.4-56.5); zygomatic breadth, 42.5 (40.7-44.2); mastoid 

 breadth, 27 (25.7-28.2) ; length of nasals, 20.5 (18.9-22.3) ; length of 

 mandible, 41.9 (40.9-43.3) ; maxillary tooth row, alveoli, 14.5 (14-15). 

 Females average slightly smaller. For detailed measurements of 

 specimens see page 35. 



Weight. — An adult male collected September 6 in the Jemez Moun- 

 tains, New Mexico, weighed IJ pounds. 



Type specimen, — No. 1636, U. S. National Museum. Skull of young 

 adult, not sexed (teeth little worn). Collected in September, 1853, 

 by F. Kreutzfeldt; original number 22. The museum catalogue 

 shows that the skin (No. 501) was formerly preserved in the collec- 

 tion, but it has been lost for many years.^ 



Remarks. — So far as known the ranges of Cynomys gunnisoni and 

 C. leucurus do not actually meet at any point, although, as stated by 

 Cary,^ they are separated by only a very narrow strip in the Cimarron 

 region. Though so much alike in general characters the two species 

 seem perfectly distinct, with no evidence of intergradation. While 

 chiefly a Transition Zone form, gunnisoni is common and at home in 

 the Upper Sonoran valleys within its range, as throughout suitable 

 places in the upper Eio Grande and San Luis Valleys, Colorado. 

 The range of gunnisoni nearly if not quite meets that of the black- 

 tailed prairie-dog at several points m the eastern foothill region of 

 Colorado. Prof. Lantz noted a colony of gunnisoni in South Park, 

 Colorado, in which black and partly black individuals were common, 

 a dozen or more melanistic specimens being seen. 



This dark form of C. gunnisoni intergrades directly with the paler 

 race, next described, of the more arid parts of New Mexico and Ari- 

 zona, but the two subspecies are well marked and the area of intergra- 

 dation is smaU. 



Specimens examined. — Total number, 111, as foUows: 



Colorado: Antomto, 2; Cascade, 1 ; Castrel's Ranch (Park County), 2f Cochetopa 

 Pass, 30 (including type skull); Colorado City (northwest of), 3;^ Colorado 

 Springs (west of), 1; Divide (Teller County), 2f Florissant, 2;* Fort Garland, 

 20 (including some older skins labeled "Fort Massachusetts"); Fremont 

 County, 2f Head of Rio Grande, 1;^ Pike's Peak, 3; Poncha Pass, 2f Querida, 

 2f Saguache, 4; Salida, 5;^' « Southfork, 2; Tarryall Creek (Park County), 1;* 

 Twin Creek, 1 f Twin Lakes, 1 ; Wagon Wheel Gap, 12.3, 4, e 



New Mexico: Costilla Pass, 3; Coyote Creek, 2; Gallinas Mountains, 1; Jemez 

 Mountains, 1; La Jara Lake, 1; Moreno Valley, 2; Tree Piedras, 2. 



1 See Lyon and Osgood, Bull. 62, U. S. Nat. Mus., pp. 161-162, 1909. 



2 North Amer. Fauna No. 33, p. 95, 1911. 



3 Collection Mus. Comp. Zool. 

 « Collection E. R. Warren. 



6 Collection Field Mus. Nat. Hist 

 6 Collection Amer. Mus. Nat. Hist 



