Origin of Different Kinds of Adaptations 349 
its environment can easily be overstepped without danger. 
The enormous claw of the fiddler-crab must throw the 
animal out of all symmetrical relation with its environment, 
and yet the species flourishes. The snail carries around a 
spiral hump that is entirely out of symmetrical relation with 
the surroundings of a snail. 
These facts, few though they are, yet suffice to show, I 
believe, that the relation of symmetry between the organism 
and its environment may be, and is no doubt in many cases, 
more perfect than the requirements of the situation demand. 
The fact that animals made unsymmetrical through injuries 
(as when a crab loses several legs on one side, or a worm its 
head) can still remain in existence in their natural environ- 
ment, is in favor of the view that I have just stated. By 
this I do not mean to maintain that a symmetrical form does 
not have, on the whole, an advantage over the same form 
rendered asymmetrical, but that this relation need not have 
in all forms a selective value, and if not, then. it cannot be 
the outcome of a process of natural selection. 
To sum up: it appears probable that the laws determining 
the symmetry of a form are the outcome of internal factors, 
and are not the result either of the direct action of the. en- 
vironment, or of a selective process. The finished products 
and not the different imperfect stages in such a process, are 
what the inner organization offers to the environment. 
While the symmetry or asymmetry may be one of the numer- 
ous conditions which determine whether a form can _ per- 
sist or not, yet we find that the symmetrical relations may 
be in some cases more perfect than the environment actually 
demands ; and in other cases, although the form may place 
the organism at a certain disadvantage, it may still be able 
to exist in certain localities. 
