VoL, 13 ! December 19, 1923 No. 21 
a 
JOURNAL 
OF THE 
WASHINGTON ACADEMY 
OF SCIENCES 
BOARD OF EDITORS 
Sipney PAIGE E. D. WILLIAMSON E. P. Ki.urpe 
GEOLOGICAL SURVEY GEOPHYSICAL LABORATORY NATIONAL MUSEUM 
ASSOCIATE EDITORS 
H. V. Haran S. A. Ronwer 
,» BOTANICAL SOCIETY ENTOMOLOGICAL SOCIETY 
N. Howuister G. W. Srosz 
BIOLOGICAL SOCIETY GEOLOGICAL SOCIETY 
W. F. Mreaczers J. R. SwANToN 
PHILOSOPHICAL SOCIETY ANTHROPOLOGICAL SOCIETY 
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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. ae for mailing at special rate of postage provided for 
in Section 1103, Act of October 3, 1917, Authorized on July 3, 1918. 
