HOMOTYPOSIS IN THE VEGETABLE KINGDOM. 
341 
Al3Solute Dimensions of Mnshroom Gills. 
Character. 
Mean. 
S. I). 
Coefficient 
of variation. 
S. I), of 
array. 
Percentage 
variation. 
Direct homo¬ 
typic correlation. 
Length. . 
Breadth . 
19-1817 + -0831 
6-8529 ±-0331 
4-0282 -r -0587 
1-6047 ± -0234 
20-9969 
23-4164 
2-0510 
1-0859 
50 - 92 
67-67 
-8607 [+ -0053] 
-7363 [± -0094] 
Cross-correlations. 
Length and breadth, organic . . j ’ 7000 ± '0105 
Length and breadth, homotypic . ; ■b275[± "0125] 
The results here given seem to be of consideralTe suggestiveness. While the two 
means and standard deAuations ditfer very considerably, the coefficients of variation 
for the length and breadth of the gill are ap])roximately equal, and in addition 
very high. This is precisely A^diat we might exj^ect when dealing with a series 
of organisms in various stages of growth. Further, the variability of the individual 
as compared with that of the race is reduced immensely heloAv the 80 to 00 per cent, 
with Avhich our previous investigations have made us familiar. This might again he 
anticipated as a result of heterogeneity in the stage of growth. Tlie oig’anic correla¬ 
tion of length and breadth, as AA^ell as the homotypic correlations of tire same two 
characters, both direct and cross, are all A’ery high, and the latter are much beyond 
what we might legitimately put to the credit of the pure homoty})osis factor. It seems, 
therefore, someAvhat hazardous to consider how far they satisfy the relationshi]) sug¬ 
gested in the introductory part of this paper. The direct homotypic correlations for 
length and breadth are not approximately e({ual as we might expect; this suggests 
that groAvth may he a somewhat more marked factor in the length than the breadth 
of the gill. If we take the product of direct homotypic correlation with the organic 
correlation, this ought, on our hypothesis, to give us roughly the cross-homotypic 
correlation. We have the following results ;— 
Product of direct homotypic length correlation with organic length- 
breadth correlation.= '6025. 
Product of direct hom(3ty})ic breadtli correlation with organic length- 
breadth correlation.= ‘5154. 
Product of mean of direct lioinotypic breadth and length correlation with 
organic length-breadth correlation.= ‘5590. 
These numbers have to be compared with the cross homotypic lengtli-hreadth 
correlation, i.e., with '0275. 
