PROOFS OF EVOLUTION. 
55 
XII. 
PROOFS FROM REVERSION. 
One of the most curious facts of Evolution is 
the tendency to revert to ancestral forms. This 
at first seems to weaken the theory of Descent, 
but in reality it gives it great support. It is all a 
question of environment. If that remains the 
same, there will be little change in life-forms. 
For this reason the King-Crab and the Nautilus of 
to-day are quite similar to their fossil parents. If 
former life-conditions are restored, what is more 
natural than retrogression? 
But even here, paradoxical as it may seem, 
there is really progress, for Evolution always 
insists on the readjustment of organs to environ¬ 
ment. The changes are best for the animal 
under the circumstances, and therefore truly 
an advance for him. This tendency to reversion 
is shown by the stripes on some horses and 
mu l es — a survival of the stripes on the wild 
horse, such as we see on the zebra; also, by the 
