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New Species of Fossils and Remarks upon Others. 167 
and Marcy, under the generic name of Megistocrinus, published, in the 
Memoirs of the Boston Society of Natural History, three species that 
were collected in the Niagara Group, at Bridgeport, viz: S. infelix, 8. 
necis, and S. marcouanus. Prof. Hall, at that time, regarded these 
species as identical with S. christyi, though in the 28th Report, above 
referred to, he classed as synonyms only S. infelix and S. marcouanus. 
I am enabled now not only to distinguish the three species of Winchell 
and Marcy, but to determine three new species from the same quarries. 
The inferior specimens studied by these gentlemen, and the poor 
illustrations furnished by the Boston Society, no doubt led to the 
many erroneous conclusions that have been formed respecting these 
Bridgeport crinoids, for there can not be found, in any genus, four 
Species more marked and distinct, from each other, than S. christy?, 
S. infelix, S. necis, and S. marcouanus. Indeed, one might hesitate 
before referring them all to the same genus, and if S. marcouwanus were 
found in rocks of another age, itis more than probable it would be de- 
fined as a new genus. But from the great abundance and large size 
of the crinoids at Bridgeport, we may fairly presume, that they lived 
in a situation most favorable for their development, and hence, that we 
may expcct to find extreme variations in the forms belonging to the 
same genus. This great diversity is all the more likely in a genus 
having such an extended geographical range as Saccocrinus. For 
this reason a new definition of the generic characters may not be 
inappropriate. 
Saccocrinus, Hall, 1852. 
Body more or less elongated, urn-shaped, obconoidal, or sack-like in 
form. Basal plates, three; radials, three by five; secondary radials, 
from one to four by ten; tertiary radials, in species where they exist, 
usually, one by twenty; regular interradials, ten to seventeen; inter- 
secondary radials, variable in number; azygous interradials, one, 
resting upon the basals, succeeded by three, and above this more or 
less numerous in different species. Arms, ten, twenty or thirty, com- 
y) 9 5) 
posed of a double series of plates, and bifurcating after they become 
free one or more times. 
SACCOCRINUS MARCOUANUS, W. and M. 
Plate IV., fig. 1, view of the azygous side of a specimen a little distorted and peculiar, 
broken off at the constriction below the vault, natural size; fig. la, view of the vault of an- 
other specimen, natural size. 
(Megistocrinus marcouanus, Winchell and Marcy, 1865, Mem. Bost. 
Soc. Nat. Hist. ) 
