Preliminary Report on Fossil Mammals From Porto Rico, With Descriptions of a New Genus of Ground Sloth and Two New Genera of Hystricomorph Rodents

CONTENTS Poge Introduction. ....................................... Systematic trentmcnt ................................ New genus of ground sloth ....................... Descriptioii of Ilo'alocrtr~s otZontt%gorirts. ........................ 195 Skull ..................................................... 195 Mensuremetits of crunium.. .................... . 196 Mnndibulnr 1'tmus.. ....................................... 196 hfensurements of ~ A I U U S . .................................. 196 Humerus ...............................