CONTRIBUTIONS 



THE NATURAL HISTORY 



UNITED STATES OF AMERICA. 



LOUIS AGASSIZ 



SECOND MONOGRAPH. 



IN FIVE PARTS.— I. ACALEPHS IN GENERAL.— II. CTENOPIIOR^.— III. DISCOPHORiE.— IV. IIYDROIDJS. 

 -V. HOMOLOGIES OF THE RADM^;^X,WTH FORTY-SIX PLATES. 



3 1882 



BOSTON: 

 LITTLE, BEOWN AND COMPANY 



LONDON: TRUBNER & CO. 



186 0. 



