VE Darwin, and after Darwin. 
full agreement with the theory of evolution, while 
they offer serious difficulties to the theory of special 
creation. As Darwin remarks, it is hard to imagine 
conditions of life more similar than those furnished by 
deep limestone caverns under nearly the same climate 
in the two continents of America and Europe; so 
that, in accordance with the theory of special creation, 
very close similarity in the organizations of the two 
sets of faunas might have been expected. But, 
instead of this, the affinities of these two sets of 
faunas are with those of their respective continents— 
as of course they ought to be on the theory of 
evolution. Again, what would have been the sense 
of creating useless foot-stalks for the imaginary sup- 
port of absent eyes, not to mention all the other 
various grades of degeneration in other cases? So 
that, upon the whole, if we agree with the late Prof. 
Agassiz in regarding these cave animals as furnishing 
a crucial test between the rival theories of creation 
and evolution, we must further conclude that the 
whole body of evidence which they now furnish is 
weighing on the side of evolution. 
So much, then, for a few special instances of what 
Darwin called rudimentary structures, but what may 
be more descriptively designated—in accordance with 
the theory of descent—obsolescent or vestigial struc- 
tures. It is, however, of great importance to add that 
these structures are of such general occurrence through- 
out both the vegetable and animal kingdoms, that, as 
Darwin has observed, it is almost impossible to point 
to a single species which does not present one or 
more of them. In other words, it is almost impos- 
sible to find a single species which does not in this 
