On August 27, 1826, over 130 years ago, Dr. David Douglas met an Indian near the site of the present town of The Dalles, Oregon, while traveling from Walla Walla to Fort Vancouver, Washington. Douglas obtained from the Indian a mountain sheep that had been killed near Mount Adams, Washington. This specimen provided the basis for his description of Ovis californianus (Ovis canadensis californiana). At the time (1826), mountain sheep ranged over much of the mountains and desert regions of California, Oregon, Washington, and British Columbia. At present the subspecies is nearly extinct in California, extinct or nearly so in Oregon, and reduced to perhaps one band in Washington, in the vicinity of Bauerman Ridge and Mount Chopaka. A few small bands are still present in British Columbia (see Cowan, American Midland Naturalist, 24: 557-558. 1940). In 1889 the display collection of big game animals at the Museum of Natural History, University of Kansas, was being built, and Professor L. L. Dyche made an expedition to Mount Chopaka, Okanogan County, Washington, to collect specimens of mountain sheep. According to the Museum catalogue no less than 54 specimens of O. c. californiana were brought back to the Museum by the expedition. Of these 54, according to the catalogue, 5 are without skulls, 8 specimens have the skulls mounted within the skins, and 4 are on deposit elsewhere. A total of 37 skulls, of which 33 are males and 4 are females, have been studied by us. This is the largest series of North American bighorns from any one locality (Mount Chopaka) known to us to exist in any museum (see also Cowan, op. cit., 509). Much of the flesh of most of these skulls was cut away in the field, but only recently have the skulls been more completely cleaned in order to check accurately the age-variation and individual variation.