OBSERVATIONS 



GENUS UNIO, 



TOGETHER WITH 



DESCKIPTIONS OF NEAV SPECIES IN THE FAMILY UNIONID.E 



READ BKFORE THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA AND 

 PUBLISHED L\ THEIR JOURNAL. 



ISAAC LEA, LL.D., 



VICE PUES. ACAD. NAT. SCI. ; MEM. OF THE AM. PHIL. SOC. ; OF THE ZOOL. 30C. 

 OF LONDON ; OF THE IMPEUIAL SOC. OF MOSCOW, AC. AC. 



WITH THIRTEEN PLATES, 



VOL. VI. 

 PART I . - 1 8 5 7 



r MIL A DEL Pin A : 

 PRINTED FOR THE AUTHOR 



MEKBIHEW 1 THOMPSON PltlNTKKS. 



