7? 17 



THE MOLLUSCAN FAMILY 

 PLANORBIDAE 



By 



FRANK COLLINS BAKER . 



Curator, Museum of Natural History, ^m.tyiiu& 

 University of Illinois 



Collation, Revision, and Additions 



By 

 HARLEY JONES VAN CLEAVE 



THE UNIVERSITY OF ILLINOIS PRESS 

 URBANA : 1945 



