i 
HEXACRINIDZ. 765 
the summit covered by a large, single oral plate, from the sides of which the 
covering pieces pass out to the arms. Column large compared to the size of 
the species; composed of high joints with serrated edges. 
Horizon and Locality. — Kinderhook group, Le Grand, Marshall Co., 
Towa. | 
| Types in the collection of Mr. Wm. F. E. Gurley, Danville, Ils. 
Dichocrinus levis Hatt. 
Plate LX XVII. Figs. 7a, 6, ¢. 
1859. Hat; Suppl. Geol. Rep. Iowa, Vol. I, p. 83. 
1881. W. and Sp.; Revision Paleocr., Part II., p. 84. 
A beautiful little species. Calyx goblet-shaped, obconical to the basi- 
radial suture, not expanding above; the cross section slightly hexagonal. 
Plates remarkably thin and flat, their surfaces thickly covered with small 
granules. 
Basals forming a small obconical cup, which extends to about one third 
the height of the calyx, and sometimes a little higher. Radials nearly as 
long as wide; the sides parallel, except in the two posterior rays, where they 
are wider above; the lower faces moderately convex; the upper almost 
straight; facets small, occupying but one third the width of the plates; 
their lower margins slightly thickened. Costals two, a little wider than 
long; the second sharply pentangular. Distichals almost as wide as the 
costals, the line of union between the first and second less distinct than that 
between the succeeding joints; the second giving off either a very large 
pinnule or an arm; in the former case sometimes another bifurcation takes 
place higher up. Arms uniserial, long, rather stout, very little tapering ; 
composed of cuneate joints alternately arranged, which at the tips do not 
touch the opposite side of the arm. Pinnules long, very stout, and not in 
contact; the joints as wide as long. Interradials not visible from a side 
view. Anal plate a little higher than the radials, narrowest at the upper 
end, and distinctly angular at the basi-radial suture. Anus placed near the 
margin of the ventral disk, in the middle of a small protuberance. Column 
round, small. 
Horizon and Locality. — Lower Burlington limestone ; Burlington, Iowa. 
The specimens figured are in the collection of Mr. F. M. Fultz, of Bur- 
lington, Iowa. . 
“ fee of 
