THE FOSSIL BISON OF NOKTH AMERICA. 

 By Frederic A. Lttcas, 



Curator, Division of Comparatire Anatomy. 



The aim of this paper is to assign definite characters to the various 

 species of bison occurring in a fossil condition in North America and 

 to disentangle the complicated synonymy in which they have been 

 involved. With the exception of Bison crassicornis and Bos arizonica 

 the types of the various alleged species have all been examined, and to 

 aid in defining the species and to unravel the synonymic snarl either 

 the types or characteristic examples of all species are herein figured. 



I wish to express my thanks to Profs. J. C. Branner and C. W. 

 Greene, Dr. Josua Lindahl, Mr. S. N. Rhoads, and Prof. S. W. Willis- 

 ton for photographs and information concerning various specimens, and 

 to Prof. O. 0. Marsh, the Academy of Natural Sciences, Philadelphia, 

 and to the University of Pennsylvania for the loan of specimens. 



While remains of fossil bison are not uncommon in North America, 

 they occur as a rule in such a scattered and fragmentary condition and 

 the various parts so disassociated that at present it is impossible to 

 correlate the teeth with the other portions of the skeleton and to diag- 

 nose the species in a thoroughly satisfactory manner. The best that can 

 be done is to use such material- as we have and endeavor to distinguish 

 the species by their horn cores, and after going over the subject care- 

 fully I am convinced that in spite of an admitted amount of individual 

 variation the horn cores afiord very good specific characters. They do 

 not difier among themselves any more than do other portions of the 

 skeleton, and in the present case they are infinitely preferable to scat- 

 tered teeth. Moreover the differences between the skulls of such spe- 

 cies as B. bison and B. oceidentalis indicate that the various species 

 could be well differentiated did we possess suflicient material. 



Little or no attempt has been made in this paper to name or describe 

 individual teeth, since, so far as known, these so closely resemble the 

 corresponding teeth of the existing bison that really the best that can 

 be done is to make a guess at the species from the locality in which 

 they were found. 



So far as can be judged by the appearance of the specimens or the 



Proceedings U. S. National Museum, Vol. XXI— No. 1 172. 



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