_O. m. columbianus_ abounds along the coast ranges of British Columbia, and extends into Alaska, probably merging in the neighborhood of the Copper River into _O. kennedyi_, the western-most member of the genus. The extreme western record for goat is the Matanuska River, not far from the head of Cook Inlet. Horns from this locality, however, do not show the characteristics of Kennedy's goat. No goat are reported in the vicinity of Mt. McKinley, but they are found along the Copper River for a considerable distance inland, and there is some evidence of their occurrence on the north side of Mt. St. Elias. It may be well to remark here that while _O. kennedyi_ is a valid species, founded on abundant material, no living specimens have been seen by a white man so far as is known, nor have we any information concerning the limits of its distribution. _O. m. columbianus_ is by far the largest and handsomest member of the genus, unless _O. kennedyi_ proves on further investigation, to excel in these respects. It is, therefore, surprising that the great differences in size and other characteristics, which distinguish this type from the goat in the United States have not been previously recognized. The animals south of the Canadian border and still in the main range of the Rockies, upon comparison with the preceding types, were found to be much smaller, in fact the smallest of all the subspecies and were characterized by shorter but still relatively narrow skulls. The specimens of this type under consideration having been killed in the Bitter Root Mountains, the subspecific name of _O. m. missoulæ_ was given them by Dr. Allen. This is the fourth and last type to be described, although these animals from the Bitter Root Mountains were the first goat known to transcontinental explorers. This is the goat usually hunted by American sportsmen and its range probably extends from the southeastern limits of the genus in Montana and Idaho to the Canadian border, where like _O. montanus_ it passes imperceptibly into _O. m. columbianus_. The extreme southerly limit of the goat in the Rockies is the Sawtooth Mountains and the Salmon River in Idaho. It does not reach the Tetons, in Wyoming, nor does it occur in the Yellowstone Park. The question of its absence in these localities will be discussed later in this paper. [Illustration: WHITE MOUNTAIN GOAT AND MOUNTAIN SHEEP IN THE NEW YORK ZOOLOGICAL PARK.] [Illustration: WHITE MOUNTAIN GOAT AND MOUNTAIN SHEEP IN THE NEW YORK ZOOLOGICAL PARK.] To sum up, the two American subspecies are smaller than their Canadian relatives and the type from the Cascade Mountains possesses a broad skull, in direct contrast to the narrow skulls of all other goats, both American and Canadian. CAUSES GOVERNING DISTRIBUTION.