JOURNAL 



OF THE 



WASHINGTON ACADEMY 

 OF SCIENCES 



VOLUME X, 1920 



BOARD OF EDITORS 



J. Franklin Meyer Robert B. Sosman S. F. Blake 



BUREAU OF STANDARDS GEOPHYSICAI, LABORATORY BUREAU OF PLANT INDUSTRY 



ASSOCIATE EDITORS 



H. V. Harlan S. A. Rohwer 



BOTANICAI, SOCISTY ENTOMOLOGICAL SOCIBTY 



N. HOLLISTER F- B. SiLSBEE 



BIOLOGICAL SOCIETY PHILOSOPHICAL SOCIETY 



Sidney Paige J- R- Swanton 



GEOLOGICAL SOCIETY ANTHROPOLOGICAL SOCIBTY 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST, AND SEPTEMBER, WHEN MONTHLY 



BY TBS 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



2 I I CHURCH STREET 



EASTON, PA. 



