SMITHSONIAN C () N T U I li U T I () K S T ( • K N ( MV I. K D fi K 



A M E M () I R 



EXTINCT SLOTH TRIBE 



NORTH AMERICA 



JOSEPH LEIDY, M.D., 



i'HOfessok of anatomy in the univebsity of Pennsylvania, anp cdbator of the AOAOKiMv of 



NATURAL SCIENCES OF PniLADELPIIIA, 



IaCCEPTED FOB PI'BLIC ATION, I) E f E JI B E R , ISSo.] 



