4 Cincinnati Society of Natural firstory. 
Ve 
EUPACHYCRINUS MAGISTER. DN. Sp. 
Flate l., Fig. 1, basal wew ; Fig. 2, azygous side mew. 
This species is very large; calyx low and broad, somewhat 
saucer-shaped, bulged a little upon the azygous side, height about 
half the width, sutures deep, excavation extending about half the 
thickness of the plates, plates very strongly tuberculated, tubercles. 
conical, elongated, and irregular in form and distribution. 
The five basal plates are sunk in a cavity on the under side, 
projecting only half their length beyond the column; even this 
projection is tubercular; they form in the interior of the calyx a 
pyramid, which is pierced at the summit by a five-rayed opening, 
connecting with the canal in the center of the column; the points. 
of the rays are rounded. The basal plates are made. pentagonal 
by the truncation made at the points of the rays for the central 
canal. The diagrammatic views which have been made of the 
basal plates in this genus are incorrect in so far as they indicate a 
pentagonal opening with the angles directed toward the sutures, 
instead of truncating the plates, with a concave depression, for the 
five-rayed opening to the columnar canal. The two basals on the 
azygous side of the species before us are larger than the others, 
being nearly as large as the other three. 
The subradials are very large, extend into the basal cavity and 
curve very gently upward: three are hexagonal, the two longer 
sides unite with the subradials, the two upper sloping sides, uniting 
with the first radials, are a little shorter, and the two under sides, 
uniting with the basals, are very short; two are heptagonal, the 
one upon the right of the first azygous plate being much larger, 
and, except the two short sides uniting with the basals, the other 
sides are of subequal length; the one upon the left has, in addition 
to the two short sides uniting with the basals, a short side adjoining 
the second azygous plate. Four of the first radials are pentagonal, 
twice as wide as high; the upper face is the full width of the 
plates, and projects over the interior of the calyx, so as to give the 
appearance of having great thickness when viewed from above. 
The other first radial, upon the right of the azygous plates, is 
quadrilateral, except a very slight truncation by the second 
azygous plate below the depth of the suture. The first radial is 
separated from the second, or brachial piece, on the outer face, by 
a wide suture, but within a crenated ridge extends from one angle 
of the plates to another, forming a pentagon, except as separated 

