144 University of California Publications in Zoology [Vol. 10 



locating a band of sheep in the vicinity of Mount Baxter, twelve 

 miles in an air line northwest of Independence. Inyo County. 

 Pour of the animals were secured during October, 1911, and 

 these, together with the Museum's specimens of the desert and 

 Rocky Mountain bighorns enumerated in Table I. form the basis 

 of the present study. 



Ovis cervina sierrae, new subspecies 

 Sierra Nevada Bighorn 



TYPE: Male, age about live years; skin, horns and complete 

 skeleton, no. 16360, Mus. Vert. Zool. ; east slope .Mount Baxter, 

 11. («)(i feet. Sierra Nevada, Inyo County. California; October 

 20, 1!H1 ; collected by 11. A. Carr; orig. no. 659. 



Diagnostic Characters: Resembles Oris c. nelsoni C. II. 

 Merriam (1897, p. 217) but general size greater, ears and tail 

 shorter, coat grayer and very much heavier, and horns in cross- 

 seetion at base more nearly of a circular outline than triangular. 

 Resembles Ovis c. cervina Desmarest (see Allen, 1912, p. 2:!). 

 but size slightly less, pelage not quite so heavy, coloration very 

 much paler, and horns in cross-section at base not triangular. 



Comparative Features: Pelage. — The sheep of the high 

 Sierra ' Nevada, as just characterized, shows an important 

 adaptive feature evidently correlated with the coldness of its 

 habitat, namely, superabundant pelage. This alone readily dis- 

 tinguishes it from 0. c. nelsoni. Seasonal variation has of course 

 been taken into account in determining this difference. In detail, 

 this greater degree of hairiness shows itself conspicuously on the 

 rump, where the hair of the white patch is 47 millimeters deep 

 instead of only 20 millimeters as in nelsoni of the same season; 

 the ears of the Sierran form are far more abundantly clothed 

 both outside and inside: the nuchal mane is prominent, the con- 

 stituent hairs 200 millimeters back of the ears being 82 milli- 

 meters long as against 45 in nelsoni; the scrotum and insides 

 of thighs are well clothed with hair in sierrae, where nelsoni is 

 scantily haired. In tine, the whole hirsute equipment of sierrai 

 as compared with Unit of nelsoni corresponds to what one would 

 expect in animals of cold and warm regions respectively. In 



