/\&-' r UA- 



-' 



5 



SMITHSONIAN MISCELLANEOUS f OI^ECTIONS. 



227 





ARKANGEMENT 



. <- 



OF THE 



FAMILIES OF MOLLUSKS. 



PREPARED FOR THE SMITHSONIAN INSTITUTION 



BY 



THEODORE GILL, M. D., PH.D. 



O 



- 





WASHINGTON: 

 PUBLISHED BY THE SMITHSONIAN INSTITUTION, 



FEBRUARY, 1871. 



