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166 Cincinnati Society of Natural History. 
these streams, is the result of the presence of conditions to which these 
creatures are by nature fitted; and while a few species are more cos- 
mopolitan, owing to their greater capacity for adaptation, or to their 
remote ancestry, the great bulk of Fauna C has its range circum- 
scribed as has here been indicated. 
While the evidences upon which the theory of this discussion rests, 
from the geological and phylogenic aspects of the case, bave been thus 
hurriedly cited, there is yet another argument, resting mainly upon an 
anatomical basis, which, as above indicated, I hope, ‘after a while to 
bring out. So little is known of the close relations of these animals 
from this point of view, that I am of the opinion that the systematic 
zoologist will look with wonder and surprise upon the almost entire ab- 
sence of structural likeness in animals, even in such matters as the 
distribution of the alimentary and circulatory vessels, that may be 
associated with the widest variation in the character of the shell. 
Nevertheless, there are cases in both these families, of structural 
differences as striking as the other facts which have led to this division 
of our shells into these highly characteristic geological groups; and 
to these evidences I shall direct attention in a future article. 
NEW SPECIES OF FOSSILS AND REMARKS UPON 
OTHERS FROM THE NIAGARA GROUP OF ILLINOIS. 
By 8. A. Mizter, Esq. 
I have recently had the opportunity of examining a very large collection 
of crinoids belonging to W. C. Egan, Esq., from the quarries at Bridge- 
port and Cicero, near Chicago, Illinois. It is, probably, the best col- 
lection ever made at those quarries, and it has enabled me to re-define 
and restore several species which, from imperfect specimens, have 
been classed as synonyms of those described from other places. 
The genus Saccocrinus was founded upon S. speciosus, from the Ni- 
agara Group, at Lockport, New York, in 1852, by Prof. Hall, In 1863, he 
described S. christy from the Niagara Group, at Waldron, Indiana, 
which is beautifully illustrated in 28th Rep. N. Y. St., Mus. of Nat. 
Hist., pablished in 1879. In 1867, in the 20th Rep. he characterized 
S. semiradiatus, from Racine, Wisconsin. In 1875, in Ohio Pal., vol. 
ii., Hall and Whitfield defined, from the Niagara Group, at Yellow 
Springs, Ohio, S. ornatus, and S. tennesseensis. In 1865, Winchell 
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