The Theory of Sexual Selection. 409 
the latest results of scientific classification —seeing this, 
it becomes impossible to doubt that the radiate form 
is due to some morphological reasons of wide gener- 
ality. Whether these reasons be connected with the 
internal laws of growth, or to the external conditions 
of environment, I do not pretend to suggest. But I 
feel safe in saying that it cannot possibly be due to 
any design to secure beauty for its own sake. The 
very generality of the radiate form is in itself enough 
to suggest that it must have some physical, as dis- 
tinguished from an zsthetic, explanation ; for, if the 
attainment of beauty had here been the object, surely 
it might have been even more effectually accomplished 
by adopting a greater variety of typical forms—as, for 
instance, in the case of flowers. 
Coming then, lastly, to the case of brilliant tints in 
the lower animals, Mr. Darwin has soundly argued 
that there is nothing forced or improbable in the 
supposition that organic compounds, presenting as 
they do such highly complex and such varied chemical 
constitutions, should often present brilliant colouring 
incidentally. Considered merely as colouring, there 
is nothing in the world more magnificent than arterial 
blood ; yet here the colouring is of purely utilitarian 
significance. It is of the first importance in the 
chemistry of respiration ; but is surely without any 
meaning from an xsthetic point of view. For the 
colour of the cheeks, and of the flesh generally, in 
the whzte races of mankind, could have been produced 
quite as effectually by the use of p'gment—as in the 
case of certain monkeys. Now the fact that in the 
case of blood, as in that of many other highly 
coloured fluids and solids throughout the animal 
