758 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



BISON OCCIDENTALIS Lucas. 



(riates LXV, LXVI.j 



lii^on antiquus Stewart. Kan. Univ. Quar., VI, July, 1897, p. 127, pi. xvii. 



Bison occidentaliH Lucas, Science, November 11, 1898, p. 678. 



Bison occidentalis Lucas, Kansas Univ. Quar., VIII, .January, 189It, pp. 17, 18. 



Ty2?e.— No. 4157, U.S.KM., from Fort Yukon, Alaska; collected by 

 Sir John Richardson, Quaternary of Kansas and Alaska. 



Horn cores moderate: circumference at base equal to or slightly 

 greater thaii length along upper curve; subcircular in section, regularly 

 curved upward aiul backward. 



This species is readily distinguished from B. antiquus by its more 

 slender and proportionally longer horn cores and the fact that they are 

 directed upward and backward, as is well shown in the plates and the 

 diagram. 



An excellent figure of this species is given by Dr. J. A. Allen in his 

 Monograph of North American Bison, on Plate IV, where it is called 

 B. untUjuus. 



A practically complete skeleton of Bison occidentalis was discovered 

 in the valley of the Smoky Hill River, in Gove County, Kansas, in the 

 same deposit as remains of Ele/phas and Plafygonns and in connection 

 with small tiint arrowheads. A detailed description of thi.^ specimen, 

 which is preserved in the Museum of the State University in Lawrence, 

 Kansas, has recently been published by Mr. Alban Stewart,' but, like 

 other writers, he unfortunately confuses the species with B. crassicornis 

 and B. latifrons, which are very distinct and from wliich it may readily 

 be distinguished by the form and curvature of the horn cores. (See 

 diagram on p. 762.) As shown by the Kansas specimen, the skull is 

 larger than in B. bison and anteriorly more tapering, while the nasals 

 and premaxillaries are much longer. The orbits look more directly 

 forward than in ^. bison, and the distance between orbits and horn 

 cores is greater, the result being that the Jugals are long and slender. 



Specimens have been obtained from St. Michael, Fort Yukon, and 

 the Tatlo River, Alaska, and Gove County, Kansas. 



It is the species most nearly resembling the existing bison, with 

 which it was probably for a time contemporaneous. 



Measurements of horn cores of Bison occidentalis. 



Type No. 41,57, U.S. N.M 



Uiiiversit\ of Kansas 



Specimen from St. .Michiicl, figured by 

 Dr.J. A. .Vllcii 



Length 

 along 

 lower 

 curve. 



mm. 

 365 

 372 



•Kansas University Quarterly, July, 1«97, Ser. A, pj). 11^7-135. 



Dishiuro 



between 



tips. 



710 



875 



