316 Cincinnati Society of Natural History. 
DESCRIPTION OF NEW SPECIES OF FOSSILS FROM 
THE HUDSON RIVER GROUP, AND REMARKS 
UPON OTHERS. 
By S. A. Miuuer, Esq. 
DENDROCRINUS ERRATICUS, 0. Sp. 
Plate VIII., fig. 1, view of the azygous side, natural size ; fig. Ja, posterior or opposite view. 
Body obconoidal, rounded at the base, a little longer than the 
greatest diameter at the top of the first radials, plates smooth, sutures 
well marked, and more or less channeled above the basals, with de- 
pressions at the angles. 
Basals forming a little cup about halfas high as wide, plates pentagon- 
al, the upper sloping sides shorter than the lateral sides. Subradials 
regularly hexagonal, much larger than the basals, and nearly as wide 
as long. Three of the first radials pentagonal, length and width sub- 
equal, size about equal to the subradials; one on the left side hexag- 
onal, and larger than the other first radials; the first and second plates 
in the left anterior series, a little smaller than the first radials, the 
lower one pentagonal, and the upper hexagonal. The superior side of 
these plates is equal to the greatest width. The succeeding plates in 
the first radial series are as wide as the first radials, and have a length 
about equal to one third the width. A division takes place on the third 
plate above the first radial in each of the anterior rays, and on the fourth 
plate in the left lateral ray. Only three or four plates, in each of the 
arms, are preserved above this division, in our specimen. 
The first azygous plate is hexagonal, and a little larger than the 
subradials. The second is hexagonal, and smaller than the subradials. 
It supports upon its upper side two series of plates, the one on the 
right composed of very small plates, and the succeeding plate in the 
left series bears upon its left side a series of minute plates that inter- 
vene between it and the left anterior ray, so that, at this part of the 
azygous side, we have a width of three plates, but the marginal rows 
are very small. In our specimen we have preserved, in the azygous in- 
terradial area, seventeen plates, six of the larger ones form the central 
series, four minute plates intervene between this series and the right 
anterior free arm, and seven between it and the left anterior free arm. 
The column, as indicated by the columnar facet, is very small. 
This species bears some resemblance to D. latibrachiatus, from the 
Hudson River Group, in the Island of Anticosta, and yet it is so 
distinct as not to require any comparison. 
