xiv CONTENTS. 



ARTICLE V. A Memoir on the Extinct Sloth Tribe of North America. By Joseph Leidy, 

 M. D., Professor of Anatomy in the University of Pennsylvania, and Curator of 

 the Academy of Natural Sciences of Philadelphia. Pp. 10, and sixteen plates. 



APPENDIX. 



Publications of Learned Societies and Periodicals, in the Library of the 

 Smithsonian Institution, December 31, 1854. Part I. Pp. 40. 



