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     Ecological society of Amerca  Naturalist ´ s guide to the Americas , prepared by the Coomittee on the preservation of natural conditions of the Ecological society of America , with esaistance from numerous organizations and indivuduals , essembled and edited by the chairman , Victor E . Shelford... publication editor , Forrest Shureve .... Baltimore , The Williams Wilkins company , 1926 . xv , 761 p . front . , mapa (part double) 23 cm .