.TVtf. 6. 



MONOGRAPH Y 



FAMILY UNION ID JE , 



OR NAIADES OF LAMARCK, 



(FRESH WATER BIVALVE SHELLS,) 



NORTH AMERICA, 



ILLUSTRATED BY FIGURES DRAWN ON STONE FROM NATURE. 



BY T. A. CONRAD, 



CURATOR OP THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA, HONOUAUV MEMBER OF 

 THE GEOLOGICAL SOCIETY OF PENNSYLVANIA. 



PHILADELPHIA: 



J. DOBSON, 108 CHESNUT STREET. 



BOSTON: PERKINS & MARVIN.— PITTSBURGH: JOHN I. KAY & Co. 



LONDON: O. RICH, No. 12, RED LION SQUARE.— PARIS: ARTIIUS 



BERTRAND, FILS, RUE IIAUTEFEUILLE No. 23.- HAMBURGH: 



PERTHES & BESSER, No. 22, AM JUNGFERNSTIEG. 



E. G. DORSEY, PRINTER. 



July 1836. 



