Each one of us individually knows but little about the mountain sheep, yet each who has hunted them has observed something of their ways, and each can contribute some share to an accumulation of facts which some time may be of assistance to the naturalist who shall write the life history of this noble species. But unless that naturalist has already been in the field and has there gathered much material, he is likely to be hard put to it when the time comes for his story to be written, since then there may be no mountain sheep to observe or to write of. The sheep is not likely to be so happy in its biographer as was the buffalo, for Dr. Allen's monograph on the American bison is a classic among North American natural history works. The mountain sheep is an inhabitant of western America, and the books tell us that it inhabits the Rocky Mountains from southern California to Alaska. This is sufficiently vague, and I shall endeavor a little further on to indicate a few places where this species may still be found, though even so I am unable to assign their ranges to the various forms that have been described. For this species seems to have become differentiated into several species and sub-species, some of which are well marked, and all of which we do not as yet know much about. These as described are the common sheep of the Rocky Mountains _(Ovis canadensis_); the white sheep of Alaska _(Ovis dalli)_, and its near relative, _O. dalli kenaiensis_; the so-called black sheep of northern British Columbia (_O. stonei_), described by Dr. Allen; Nelson's sheep of the southwest (_O. nelsoni_) and _O. mexicanus_, both described by Dr. Merriam. Besides these, Mr. Hornaday has described _Ovis fannini_ of Yukon Territory, about which little is known, and Dr. Merriam has given the sheep of the Missouri River bad lands sub-specific rank under the title _O.c. auduboni_. Recently Dr. Elliot has described the Lower California sheep as a sub-species of the Rocky Mountain form under the name _O.c. cremnobates_. For twenty-five years I heard of a black sheep-like animal in the central range of the Rocky Mountains far to the north, said to be not only black in color, but with black horns, something like those of an antelope, but in shape and ringed like a female mountain sheep. From specimens recently examined at the American Museum of Natural History, I now know this to be the young female of _Ovis stonei_. That several species of sheep should have been described within the last three or four years shows, perhaps as well as anything, how very little we know about the animals of this group.