VOL. VI. MARCH, 1920 NO. 8 



AMERICAN jKLIDLAIiD 



NATURALIST 



Devoted to Natural History, Primarily 

 that of the Prairie States 



Published by the University of Notre Dame, 

 Notre Dame, Indiana 



J. A. NIEUWLAND, C. S. C, Ph. D., Sc. D., Editor ^^^oa^ 



CONTENTS 



Notes on Alabama Plants W. Wolf, 0. S. B. 151 



The Biological Significance of Selective Adsorption 



Jean Dufrenoy 159 



Sexual Dimorphism and Some of Its Correlations in the Shells 



of Certain Species of Najades. A'. M. Grier, Ph. D. 165 



The Prairie Mirage Howard C. Brown 172 



Bird Nests Found at Spring Lodge in 1919. Frank C. Evans 177 



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