1910.] ia Mendelian Population Mating at Random. 53 
Table [X.—List of Mendelian Correlations between an Individual and 
his Relatives. 
Somatic correlation. m 
Relative Gametic oe: — 
. correlation. 
General. Range. . |...p.= q. 
1 qd 1 
G0 DOS BOA TOUTES = a O—= a 
Parent 5 Hane 5 
1 q-1 1 i 
Derererleats csi: — = QO—— pe 
Grandparen 7 raed ; _ 
Brother or sister ...... ; a : z a Ms 
Uncle or aunt ......... ; sy : 0-7 : 
: 1 p+8q 1 i aed 3 
WOMSING ses cccachne cuss = is : Sosa ae 
eo 4 pt2q 16 ié 4 16 
From this table we notice that, on the Mendelian hypothesis, the parental 
and sibling gametic correlations are equal, while the grandparental, avuncular, 
and cousin gametic correlations are also equal and are just one-half of the 
former. In Table X the ancestral and collateral correlations in man and 
certain animals founded on biometric research, together with the correspond- 
ing gametic correlations found above on the Mendelian assumption of “ unit- 
characters,” are collected. 
(20) The following general conclusions can be drawn from the correlations 
for somatic characters given in Table [X. 
(i) If p>8¢ the cousin correlation is greater than the parental. Thisseems 
remarkable, but it must be borne in mind that the condition is derived from 
the Mendelian idea of “ unit-characters,” and no prediction can be made as to 
when the condition is fulfilled. The only cousin correlations worked out for 
the biometric school are those by Miss Elderton. No correlation for a single 
character in cousins was found to exceed the parental one. In eye-colour 
alone did the former approach the latter. The parental correlation in this 
case was 0°495, while the cousin correlation had the values 0°44, 0°48, and 
0:38 for male and male, male and female, and female and female respectively, 
the mean value being 0°434. 
(ii) If g is small, ie. if the recedent constituent is rare, as in the case of 
albinism in man, the correlations founded on Mendelism have low values, and 
in certain cases approach zero. For pathological characters the figures found 
by Miss Elderton were certainly much smaller than for other characters in 
