DESCRIPTIONS OF TWO NEW SPECIES OF PLEISTO- 
CENE RUMINANTS OF THE GENERA OVIBOS AND 
BOOTHERIUM, WITH NOTES ON THE LATTER GENUS. 
By James WitiiaMs Gipiey, 
Of the United States National Museum. 
Two interesting specimens, each representing an apparently unde- 
scribed species of the Bovidee, have recently been placed in my hands 
for determination. They are from widely different localities, but 
since they are from practically equivalent horizons and the genera 
to which they are referable have been closely associated by former 
writers, they may be conveniently described together. The first to 
be considered is a nearly complete skull of Ovibos, closely related 
apparently to the living species, O. moschatus. It was discovered 
by Mr. C. W. Gilmore, of the U. S. National Museum, in the Pleisto- 
cene silts along the Palisades of the Yukon, Alaska, while exploring 
that region for fossils during the summer of 1907. 
The second specimen, which I provisionally refer to the genus 
Bootherium Leidy, is from a post-glacial swamp deposit near Grand 
Rapids, Michigan. Unfortunately it consists of only the upper por- 
tion of the cranium, with complete horn-cores attached, but this 
fragment seems sufficiently characteristic to warrant description. 
The specimen is the property of the Kent Scientific Museum of 
Grand Rapids, Michigan, and was discovered by Mr. EK. R. Callen- 
beck in association with the bones of a Mastodon which were being 
exhumed by a Kent Museum field party, under the supervision of 
Mr. Herbert E. Sargent, director of that institution. 
The descriptions follow in the order in which the specimens are 
mentioned above. 
OVIBOS YUKONENSIS, new species. 
Plates LVII-LVIII. 
Type.—The greater portion of a skull, but lacking the nasals, the 
premaxillaries and most of the teeth. (Cat. No. 5728, U.S.N.M.) 
The skull is that of an old male with m? and m’, the only teeth pre- 
served, well worn. 
PROCEEDINGS U.S. NATIONAL Museum, VoL. XXXIV—No. 1627. Bei 
