OBSERVATIONS 



C«.^% 





GENUS UN 10. 



DESCllIPTIONS OF NEW SPECIES, THEIR SOFT PARTS, AND EMBRYONIC FORMS, IN 

 THE FAMILY UNIONIDJi;, 



READ BEFORE THE ACADEMY OF XATL'RAL SCIENCES OF PHILADELPHIA AND 

 ITIiLISHEIi IX THEIR JOURNAL. 



ISAAC LEA, LL. T)., 



PRESIBKNT or TlIK AC.VnK.MV OF X.VTrRAL SCIKNCKS (IF PIIll.AnK].l-lII.V. KTC. ETC. 



WITH HKaiTKEN PLATES. 



VOL. H -PAKT II. 



I'll I LA DEL P 11 1 .V: 



I'RINTKI) FOR THE AITHOK. 



