{All Rights reserved) 
BIOMETRIKA. Vol. XHI, Parts 11 and 111 
CONTENTS 
PAGE 
I. On the Sesamoids of the Knee-Joint. Part I. Man. By Karl Pearson, 
F.E.S. and Adelaide G. Davin, B.Sc. (With eighteen Plates) . 133 
II. A First Study of the Burmese Skull. By M. L. Tibdesley. (With 
eighteen Cranial Contours in text and duplicates on tissue in pocket, 
nine Photographic Plates, and two folding Tables) . . , . 176 
III. An Experimental Determination of the Probable Error of Dr Spearman's 
Correlation Coefficients. Being a paper read to the Society of Bio- 
metricians and Mathematical Statisticians, December 13, 1920. By 
" Student," (With two Diagrams in text) ..... 263 
IV. On the Mathematical Expectation of the Moments of Frequency Dis- 
tributions. Part II. By Professor Al. A. Tchoupbopf of Petrograd . 283 
Miscellanea : _ , 
(i) On a General Method of determining the successive terms, in a Skew 
Regression Line. By Karl Pearson, P. R.S. .... 296 
(ii) Note on the "Fundamental Problem of Practical Statistics" {Bio- 
metrika, Vol. xiii, p. 1) ■ 300 
(iii) Second Note on the Coefficient of Correlation as determined from the 
Quantitative Measurement of one Variate §jid the Ranking of a 
Second Variate (see Biometrika, Vol. X, p. 416). By Karl 
Pearson, P.R.S. . . . '. . . . . .302 
(iv) A Study of Women Delinquents (Review). By Ethel M. Eldebton 305 
The publication of a paper in Biometrika marks that in the Editor's opinion it contains either in 
method or material something of interest to biometricians. But the Editor desires it to be distinctly 
understood that such publication does not mark assent to the arguments used or to the conclusions 
drawn in the paper. • 
Biometrika appears about four times a year. A volume containing about 400 pages, with plates and 
tables, is issued annually. 
Papers for publication and books and offprints for notice should be sent to Professor Karl Pearson, 
University College, London. It is a condition of publication in Biometrika that the paper shall not 
already have been issued elsewhere, and will not be reprinted without leave of the Editor. It is 
very desirable that a copy of all measurements made, not necessarily for publication, should accom- 
pany each manuscript. In all cases the papers themselves should contain not only the calculated 
constants, but the distributions from which tbey have been deduced. Diagrams and drawings should be 
sent in a state suitable for direct photographic reproduction, and if on decimal paper it should be blue 
ruled, and the lettering only pencilled. • ' 
Papers will be accepted in French, Italian or German. In the last case the manuscript should be 
in Koman not German characters. Kussian contributors may use Russian but theii- papers will be 
translated into English before publication. 
Contributors receive 25 copies of their papers frecj^ Fifty additional copies may be had on 
payment of 7/- per sheet of eight pages, or part of a sheet of eight pages, with an extra charge for 
Plates; these should be ordered when the final proof is returned. 
The subscription price frotn Vol. XIII, payable in advance, will be 40s. net per volume (post free) : 
single numbers 15s. net. Volumes I — XII (1902 — 19) complete, 30s. net per volume. Index to 
Volumes I to V, 2s. net. Subscriptions may be sent to Mr C. F. Clay, Cambridge University Press, Fetter 
Lane, London, E.G. 4, either direct or through any bookseller, and communications respecting 
advertisements should also be addressed to I4r C. F. Clay. 
Owing to the uncertainty at present of the cost of binding, no prices for bound copies can be fixed, 
but the quotations current at any time for binding in the standard buckram cover will be given by 
Mr C. F. Clay on application. 
Till further notice, new subscribers to Biometrika may obtain Vols. I— XII together, in paper-covered 
parts for £15 net. 
CAMBRIDGE : PRINTED BY J. B.' PEACE, M.A., AT THE UNIVERSITY PRESS. 
