OBSERVATIONS 



GENUS U N I , 



ri)BKTiiKn WITH 



DESCRIPTIONS OF NEW SPKdIES, THEIR SOFT PARTS, AND EMBRYONIC FORMS, IN 

 THE FAMILY UNIONIDiE, 



READ BEFnRE THE ACADEMY OF NATURAL SCIENCE? OF PHILADELPHIA AND 

 PUBLISHED IN THEIR JOURNAL. 



BY 



ISAAC LEA, LL. D.. 



PKESIPKNT or THK ACADEMY OF XATPKAT, WIKXCE? <IF THILAnELrHIA, 



WITH SIXTEEN PLATES. 



VOL. <;.-PART II. 



PHILADELPHIA: 



PRINTED FOR THE AUTHOR. 



