INTRODUCTION. 1x 
Smithsonian Institution, Washington ; to the Academy of Natural Sciences 
of Philadelphia ; to the California Academy of Sciences; to the Boston 
Society. of Natural History; and to Mrs. Romeo Elton of Boston, for the 
use of valuable specimens. Finally I wish to express my gratitude to Mr. 
N. S. Shaler, Director of the ‘Geological Survey of Kentucky, and to Mr. 
Alexander Agassiz, Curator of the Museum of Comparative Zoology, for their 
liberality in providing for the accompanying plates and map, and to the 
former for valuable suggestions and information. I also wish to return 
thanks to Mr. Louis Trouvelot and to Mr. Paul Roetter for the careful 
manner in which they have executed the map and plates. 
An unexpected delay in the completion of the plates having occurred, 
several months have elapsed since the main part of the paper was put in 
type, which has afforded an opportunity to include in the Appendix several 
valuable communications which were received too late to be inserted in their 
proper connection. . These relate chiefly to the occurrence of the buffalo in 
Union County, Pennsylvania, and to the date of its extirpation in the Ohio 
Valley. Matter is also added in respect to the southern limit of the buffalo 
east of the Mississippi River, especially south of the Tennessee River, which 
somewhat modify statements made respecting this point in the main body 
of the paper. Hence the attention of the reader is especially called to these 
supplemental notes. In the Appendix will also be found an important 
communication by Mr. Shaler, “On the Age of the Bison in the Ohio 
Valley.” 
J. A. ALLEN. 
Musrum or Comparative ZooLoay, Campripcr, Mass., May 24, 1876. 
