234 BULLETIN 56, UNITED STATES NATIONAL MUSEUM. 



Description. — Following is the original description : " Ty2)e from 

 Lake Santa Maria, Chihuahua, No. 99342, male ad. U.S.N.M., Bio- 

 logical Survey Collection. Collected Sept. 16, 1899, by E. W. Nelson 

 and E. A. Goldman. Orig. No. 13974. 



" Characters. — Size large ; color dark, much darker than 'nelsoni, 

 but less dark than canadensis; horns large, massive, dark, not 

 strongly outcurved; hoofs and molars larger than in O. canadensis; 

 ears long and large, nearly double the size of those "of canadensis., 

 measuring from occiput, in dry skin, 110-llG mm.; tail long and 

 slender, measuring about 130 mm.: color pattern«similar to that of 

 canadensis. 



" Color. — Body color above and below drab-brown, darkest on 

 throat, legs and tail ; no trace of dorsal stripe ; muzzle decidedly 

 paler than rest of face; rump patch broader and more squarely 

 truncate anteriorly than in canadensis; dark color on hind leg cover- 

 ing much more of inner side of thigh than in canadensis, but much 

 less of lower leg, the white spreading broadly over the posterior and 

 inner aspects and on the inner side ending abruptly just above the 

 calcaneal joint ; whitish of chin broader and less sharply defined. 



" Cranicd characters. — Skull, as a whole, large and massive. Com- 

 pared with canadensis, orbits less prominent; frontals flatter (less 

 " dished ' in forehead) ; basioccipital narrow, its sides nearly parallel, 

 its muscular facets small and median sulcus broad; occiput (viewed 

 from behind) much narrower; depth of face(aboA'e molars) less; 

 premaxillse longer, more slender, and reaching much farther back; 

 jugal relatively small and less expanded anteriorly; lachrymal long, 

 reaching well out toward premaxilla ; paroccipital narrower and 

 more slender; lips of posterior nares (behind hamulars) thin and 

 somewhat everted [in canadensis thickened and much swollen] ; angle 

 of mandible obsolete; coronoid process lower and less expanded. 

 Molar teeth larger. Horn cores longer, with longer curve and less 

 flaring base. 



^'' Horns. — Large and heavy (fig. 34), but longer and less massive 

 than those of canadensis; upper (flat) side narrower; base less flar- 

 ing; orbital corner shortly rounded off (not produced). 



'''"Measurements. — Type specimens, male, adult: Total length, 1,530 

 mm. ; tail vertebrae, 130 ; hind foot, 425 ; height at shoulder, 900. An 

 adult female from type locality: Total length. 1,490; tail vertebra, 

 130 ; hind foot, 405 : height at shoulder, 880." 



In 1886 I noted that an adult male specimen belonging to Mr. 

 D. M. Riordan, of Flagstaff, Arizona, and killed somewhere in that 

 region, was paler in color than those from Colorado and northward, 

 taken at the same season, and had longer, more pointed ears. Far- 

 ther south, along the Mexican Boundary Line, where we found evi- 



