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Description of Some New and Remarkable Crinoids. 69 
| 
- DESCRIPTION OF SOME NEW AND REMARKABLE 
| CRINOIDS AND OTHER FOSSILS OF THE HUDSON 
RIVER GROUP, AND NOTICE OF STROTOCRINUS 
BLOOMFIELDENSIS. 
By S. A. MILuer, Esq. 
PALAASTER EXCULPTUS, 0. Sp. 
Plate I., fig. 1, natural size. 
Pentagonal ; rays a little longer than the diameter of the body ; 
diameter of the body about 93-100 inch ; length of ray measuring to 
the center of the body or disc, about 14 inches; breadth of a ray at 
the junction with the body, about 57-100 inch; rays obtusely pointed. 
The marginal range consists of somewhat quadrangular plates, hav- 
ing a width a little greater than the length; the first eight of these 
. have a length of } inch, and there are about eighteen in the length of, 
an inch, and not far from twenty-five in each range, though the speci- 
men does not permit us to make the count with certainty. The sur- 
face is strongly tubercular, and was probably spinous. 
a ~The adambulacral range consists of about twenty-eight plates, on 
a each side of a ray; they are narrower than the marginal plates, but 
:! have about the same length. Each plate bore strong spines, and some © 
of them, preserved on our specimen, have a length greater than the 
length of a plate. A single, somewhat pentagonal or irregular axillary 
plate, rests between the terminal marginal plates and the angle formed 
by the junction of the adambulacral plates. The extension of the 
wedge-shaped marginal plates into this angle is by gaping, and the 
axillary plate seems to fill this gape and to rest upon the extension of 
the marginal plates, supported by four adambulacral. plates, which 
abut against it. 
The ambulacral plates have their greatest length across the rays, 
thus providing a wide ambulacral furrow. Each plate is furnished 
with a sharp ridge in the middle, that curves slightly outward, 
from the center toward the adambulacral range, increasing in height, 
until it approaches or abuts against the adambulacral plate. The 
plates have a length in the direction of the rays one half greater than 
in P. granulosus, the ridge is higher and stronger, and occupies the 
central part of the plate, instead of commencing at the outer posterior 
angle, and terminating on the anterior inner angle of one plate, and re- 
4 versing this direction on the next adjoining plate, as in P. granulosus. 
_. The character of these plates alone will, therefore, serve to distinguish 
