182 Barrande— Origin of Paleozoic Species. 
interesting matter, that we feel justified in making considerable 
extracts, especially from the closing Résumé général :— 
“T. Relative importance of Cephalopods. As regards organiza- 
tion, this order [Cephalopoda] is the first among Mollusks. It 
can al; 
innumerable. : 
Thus far, the Cephalopods may be considered as oceupy1g 
or disputing the first rank * *, but, in other respects, we mus 
dail that the preéminence belongs to the tribe of Trilo- 
ites. ‘They ess, in the first place, an incontestable an 
well-marked preéminence over the Cephalopods as rega 
riority. We know, in fact, that this tribe of Crustaceans col- 
stitutes by itself almost the whole of the Primordial Silurian 
fauna. The number of genera and species by which it is repre 
sented in this fauna is already very considerable, and we se¢ 
that it tends to increase constantly, especially in England and 
America. * * No authentic trace of Cephalopods has yet been 
recognized in the same formations. The great prolific powe? 
of the Mollusks of this order in the second et third faunas 
authorizes us to think that, if they had existed under vane 
generic and specific forms in the Primordial fauna, we show 
find their remains as frequent as those of the Trilobites in the 
