1897.] NATURAL SCIENCES OF PHILADELPHIA. 485 



d, the vertical and longitudinal (transverse) diameters of the horn- 

 cores of B. bison, measured at one-third of the distance of whole 

 length of core from base of same, are about equal, and the superior 

 (concave) surface of core well rounded, in B. antiquus the longitudi- 

 nal diameter is much the greater, and the superior (concave) sur- 

 face of core more or less flattened. 4 



The third, and by far the most interesting, of all the Alaskan 

 specimens loaned by Mr. Culin, is a large cranium of a long horned 

 fossil bison (No. 13,754), in which the frontal and occipital por- 

 tions, with their horn-cores, are intact. The upper margins of the 

 orbits and the basal suture of the nasals are also present. The 

 specimen is evidently of a fully adult male animal, and is much the 

 best preserved and strongly fossilized example of bison that has 

 come to hand. In the latter respect it is in strong contrast to the 

 other bison specimens which accompanied it from Alaska, or, in 

 fact, with any in the entire series now at the Academy. As com- 

 pared with the antiquus skull from Alaska already mentioned, it is 

 more thoroughly mineralized, and shows but slight traces of the 

 water-worn appearance so evident in the latter. Its specific gravity 

 is 1 J to If times that of the antiquus specimens. Whether they 

 all came from the same site and geological horizon we have no- 

 source of information, but the comparatively recent characters of 

 the antiquus skulls, their color and frangibility, bespeak a much 

 later age and indicate a surface exposure to the elements, so that 

 they do not greatly differ in character from the weathered skulls of 

 recent Musk Ox sent to the University from Alaska in the same 

 shipment. The large-horned specimen, which may, for the present, 

 be referred to as number 13,754, shows, in the size and curvature of 

 its horns, a very different type of bison from either B. bison or B. 

 antiquus, in these and other respects indicating their closer relation- 



4 In the type of antiquus this flattening is very marked, as also in the Alas- 

 kan specimens. In Leidy's California specimen the flattening is very slight, 

 and in cross section the horn differs very little from B. bison. Indeed, this 

 specimen in this regard is so different from the type of antiquus and from all 

 the antiquus specimens from Alaska as to raise the question of their specific 

 identity. 



Just before this article went to the printer, the author consulted a valu- 

 able paper in the Kansas University Quarterly for July, 1897, on the osteol- 

 ogy of B. antiquus, by Alban Stewart. While Mr. Stewart unfortunately 

 makes no comparisons between his fine skull of antiquus and other American 

 fossil species, and omits to mention many characters which are essential 

 in such comparisons, his paper brings out some strong distinctions between 

 typical antiquus and B. bison hitherto only conjectured because of the frag- 

 mentary state of all other specimens. 

 32 



