Ly il uy 
Vol. 13 July 19; 192Z30),\ No. 13 
JOURNAL 
WASHINGTON ACADEMY 
OF SCIENCES 
BOARD OF EDITORS 
Srpnny PatGceE ( E. D. WILLIAMSON E. P. Kruuie 
GROLOGICAL BURVEY GEOPHYSICAL LABORATORY NATIONAL MUSEUM 
ASSOCIATE EDITORS 
H. V. Haruan S. A. RonwErR 
BOTANICAL SOCIETY ENTOMOLOGICAL SOCIETY 
N. HoxuisTer G. W. Srosz 
BIOLOGICAL SOCIETY GEOLOGICAL SOCIETY 
W. F. Mreacers J. R. Swanton 
PHILOSOPHICAL BOCIETY ANTHROPOLOGICAL SOCIETY 
PUBLISHED SEMI-MONTHLY 
EXCEPT IN JULY, AUGUST, AND SEPTEMBER, WHEN MONTHLY . 
BY THE 
WASHINGTON ACADEMY OF SCIENCES 
WILLIAMS & WILKINS COMPANY 
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Entered as Second Class Matter, January 11, 1923, at the post-office at Baltimore, Md., under the 
Act of August 24,1912. Acceptance for mailing at special rate of postave provided for 
in Section 1103, Act of October 3, 1917. Authorized on July 3, 1918. 
