NO. 1172. 



THE FOSSIL BISOX OF NORTH AMERICA— LUCAS. 



ib( 



The horn core, considered to be that of ttie female, differs considera- 

 bly from that of the male, being straighter and not flattened above It 

 is keeled on convex face, the edge near the tip being quite sharp, and 

 there is a bare possibility that it may belong to a young female of some 

 species of Bison, although this is doubtful. 



Measurements of horn cores given in this paper do not include the 

 frontal pedicel, but are taken from the raised edge ol the portion cov- 

 ered by horn. Transverse diameter means greatest diameter in a line 

 parallel with the longitudinal axis of the skull; vertical diameter is the 

 greatest diameter at right angles to this. 



The dorsal views of the crania are taken perpendicularly to the plane 

 of the forehead, the posterior views at right angles to the back of the 

 skull. It is highly important that all views of crania for comparative 

 purposes should be taken in the same manner, since a slight change in 

 the angle of sight, looking down upon the skull, makes a considerable 

 apparent change in the direction of the horn cores. 



Seven species of Bison are herein recognized: Bison alleni, antiquus, 

 bison, crassicornis, ferox, !atifrons, and occidentalis. Descriptions of 

 these are given below together with the location of the type, the i)rin- 

 cipal synonymy and measurements of the more important specimens. 



BISON BISON (Linnaeus). 



Bos bison LiNN.ECS, Syst. Nat., 1758, I, p. 72. 



Bos bison var. /i, Linn.eus, Syst. Nat., 1766, I, p. 99. 



Bos americanns Gmelin, Syst. Nat., 1788, I, p. 204. 



Bison americanns Smith, Griffith's Cnv., V, 1827, p. 374. 

 Horn cores short, circumference at base usually much greater than 

 length along upper curve; subcircular in section, vertical diameter 

 slightly exceeding transverse, generally abruptly recurved; directed 

 backwards at the tip. 



Remains of this species occur abundantly in a seniifossil condition 

 at Big Bone Lick,- Kentucky, and completely mineralized specimens 

 have been obtained in Kansas. The upper portion of the skull, with 

 perfect horn cores. No. 1718, U.S.KM., was obtained by Dr. A. G. Chase, 

 at Millwood, Kansas, 25 feet below the surface. Another good speci- 

 men, the tairly complete skull of a large bull. No. 4158, U.S.N.M., was 

 collected by Dr. T. T. Minor, in the loess of .Missouri, at a locality in the 

 Winnebago Reservation. It is remarkable for the spread of the horns 

 (055 mm.) and for the size of the teeth, which equal any yet discovered. 



Measurements of horn cores of Bison bison. 



Vertical 



Trans- 



Circum- 

 ij- . verse ference .,„„„„ 



jdiameter.^i^j^^t^j.. at base. '^^^l 



No. 4158, U.S.X.M.. from loess of Mis- 

 souri 



No. 205(1. Museum Comparative Zoology. 

 No. 12456, U.S..N.M 



77 



mm. 

 247 

 300 

 84 I 280 



Length 

 aloDg 



m,m. 

 220 

 260 

 226 



^cfinft'' ll>i8tance 



lowef between 

 lower jj 



mm. 

 270 



280 



b55 

 650 

 615 



