Vol. XIII. Part IV 
October, 1921 
BIOMETEIKA 
A JOUKNAL FOR THE STATISTICAL STUDY OF 
BIOLOGICAL PROBLEMS 
FOUNDED BY 
W. F. R. WELDON, FRANCIS GALTON and KARL PEARSON 
KDITED BY 
KARL PEARSON 
CAMBRIDGE UNIVERSITY PRESS 
C. F. ^CLAY, Manager 
LONDON: FETTER LANE, E.G. 4 
also 
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WHELDON AND WESLEY, LTD., 28, ESSEX STREET, LONDON, W.0.2 
OBICAGO: CNIVEBSITY OF CHICAGO PRESS 
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BOMBAY, CALCUTTA AND MADRAS : MACMILLAN AND CO., LIUITED 
TOKYO: THE UARUZEN-KABDSHIKI-KAISHA 
Price Fifteen Shillings 
[Issued 30 November, 1921] 
