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JOURNAL 



OF THE 



WASHINGTON ACADEMY 

 OF SCIENCES 



VOLUME 11, 1921 



Robert B. Sosman 



GEOPHYSICAL LABORATORY 



BOARD OF EDITORS 

 S. F. Blake; 



BUREAU OF PLANT INDUSTRY 



Sidney Paige 



GEOLOGICAL SURVEY 



ASSOCIATE EDITORS 



H. V. Harlan 



BOTANICAL SOCIETY 



N. HOLLISTER 



BIOLOGICAL SOCIETY 



S. A. ROHWER 



ENTOMOLOGICAL SOCIETY 



F. B. SiLSBEE 



PHILOSOPHICAL SOCIETY 



G. W. Stose 



GEOLOGICAL SOCIETy 



J. R. Swanton 



ANTHROPOLOGICAL SOCIETW 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST, AND SEPTEMBER, WHEN MONTHLY 



BY THE 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



211 CHURCH STREET 



E ASTON, PA. 



