ve 
2 wen! 
TS 
408 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
supports 2 X 2 fixed palmars, and these the arms. The arm-bearing plates 
are once and a half as wide as those below or above, and in contact laterally. 
Their facets are irregularly crescent-shaped, and directed slightly upward 3 
they do not occupy the middle of the plates, but lean to the inner sides of 
the rays, and leave large interspaces between adjoining rays. By means 
of this structure the arms are formed into groups as effectually as in other 
species by the interposition of interbrachial plates. The arms, which have 
not been observed in this species, were evidently quite ponderous to judge 
from the large size of their facets, and composed of two rows of short, leaf- 
like pieces, similar to those of Agaricocrinus. Interbrachials one; the plate 
large, higher than wide, and arched by the arm-bearing brachials. First 
anal plate followed by a very long second, which rises to above the level of 
the arm bases, and rests between two short interbrachial pieces. Ventral 
disk more than three times as high as the dorsal cup; the plates large and 
of about uniform size; the anal tube occupying the central part. The 
posterior oral is the largest plate of the tegmen, and, like the other orals, is 
pushed over to the anterior side. The ambulacra are subtegminal, their 
upper portions being covered with superimposed interambulacral pieces, but 
on approaching the arms by large radial plates of a first and second order. 
The respiratory pores are large, and placed at some distance from the ambu- 
lacral openings. 
Horizon and Locality.— Keokuk group; Pilot Knob, near Louisville, Ky.; 
White’s creek, near Nashville, Tenn., and New Ross, Montgomery Co., Ind. 
fiemarks. — Miller's Alloprosallocrinus Giurleyi is a small example of 
A. conicus, in which one of the posterior rays has but two arms, 
EUTROCHOCRINUS W. and Sp. (nov. gen.). 
(Ed well, tpoxyds a wheel, xpivor a lily). 
Calyx large, wheel-shaped, narrow to the top of the radials, thence 
spreading abruptly until the sides of the dorsal cup are at right angles 
to the axis of the calyx. Ventral disk almost flat to near the base of the 
anal tube. Basal cup deep, subcylindrical, composed of three equal plates. 
Radials larger than both costals together; the first costal transversely linear, 
the second depressed pentangular. Distichals and palmars increasing in 
width upward. Ambulacral or arm openings equidistant or nearly s0 ; 
directed sidewise. Arms single or in pairs, biserial, rounded, very short and 
* 
