Stolzmann’s Theory 
are likely to persecute the hens; we may also 
grant that many cocks are handicapped in the 
struggle for existence by the excessive growth 
of certain of their feathers, but we fail to see 
how this excessive development has been caused 
by natural selection in the manner suggested by 
Stolzmann. Although it may be advantageous 
to the species for the cocks to be showy, natural 
selection can perpetuate this only by weeding 
out the least conspicuous of the cocks. But it 
is the more gaudy ones, those, according to 
Stolzmann, whose presence is beneficial to the 
species, which will be eliminated by natural 
selection. So that, in this case, that force will 
act in a manner contrary to the interests of the 
species, if Stolzmann’s idea is a correct one. 
The theory in question would therefore seem 
to be untenable. Nevertheless there is doubt- 
less some truth in the notion that too many 
males spoil the species. Thus, excessive showi- 
ness and high mortality among the males may 
be beneficial to the species. But we must not 
forget that the more beneficial it is, the stronger 
must be the tendency of natural selection to 
eliminate the males that possess the desired 
peculiarity. 
Nero-LAMARCKIAN EXPLANATION 
J. T. Cunningham makes an attempt to ex- 
plain the phenomena of sexual dimorphism on 
329 
