190 Barrande— Origin of Paleozoic Species. 
buted to a power of variation inherent in their nature and only 
controlled by the influence of the surrounding medium. Ac- 
the Silurian countries. This conclusion, immediately deduced 
the whole of the facts observed in the Silurian world, 
confirms, in a manifest manner, our preceding conclusion, 
derived from the parallel between the zodlogical and the chron- 
ological evolution of Cephalopods. Both contribute equally 
to show us how far teachings founded upon positive facts deter- 
mined by science are in discordance with the spontaneous 
intuitions of any theories whatever. 
r. Barrande enumerates in his list of Silurian Cephalopods 
25 genera and 1622 species. 
ary. 
“Upon one of the earlier pages of this volume, we have 
recalled the fact that direct observation has marvelously con- 
J 
lete discord with the observed facts of paleontology. These 
iscordances are so numerous and so well marked, that the 
composition of the real fauna would seem to have been caleu- 
lated for the express purpose of contradicting all that. the 
theories teach us ing the first appearance and the prim 
tive evolution of the forms of animal life upon the globe. | So, 
the paleontological theories are completely invalidated by reality, 
whose test they cannot sustain. It is still to be ascertain 
whether the demonstrated discordances ought to be imputed 
solely to the essential principle of the theories of descent and 
