770 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Dichocrinus conus Meek and WorrTuHen. 
Plate LX XV. Fig. 6. 
1860. Merk and Wortuxn; Proceed. Acad. Nat. Sci. Phila., p. 381; and Geol. Rep. Illinois, Vol. IT., 
p: 169, Plate 16, Figs. 5a; 6. 
1881. W. and Sp.; Revision Paleocr., Part IL., p. 83. 
Large for this genus. Calyx obconical; width and length as four to 
five; constricted at the upper end; distinctly hexagonal in outline, a keel- 
like angularity proceeding from the radial facet all the way to the lower | 
ee SS OS ae 
eta . 
end of the basals. Plates thin, without ornamentation, and united by closely 
fitting linear sutures. 
ere 
mee my 
| | Basal cup obconical, nearly as high as the radials, the sides perfectly 
straight; the basal concavity unusually small, being not larger than the 
ee 
\ | i | width of the column; the re-entering angles at the upper face deep. Radials 
lee varying in size, their length from once and a half to twice their width, 
| the antero-lateral ones wider than the others, but all increasing in width 
upwards; facets surrounded by a thickened angular rim, occupying nearly 
one third the width of the plates, and extending down to about one fifth 
their length, forming large limbs at the sides, which bend decidedly in- 
ward. Anal plate narrower than the radials, hexangular, fully twice as 
long as wide; the sides nearly parallel. All other parts of the species 
unknown. 
= ae florizon and Locality. — Lower Burlington limestone ; Burlington, Iowa. 
| ) | | Type in the Illinois State collection, Springfield. 
| yy | PEI Remarks. — Dittering from all other species in the larger size, the angu- 
aa larities which extend to the whole length of the cup, the constriction of the 
| I a | cup at the upper end, and the great depth of the radial facets, with well 
i | | _ defined limbs at the sides. 
wy 
r i | Dichocrinus inornatus W. and Sp. 
Pil F Plate LX XVIT. Figs. 12a, b. 
1890. W. and Sr.; Geol. Rep. Illinois, Vol. VIII., p. 190, Plate 16, Figs. 1 and 2. 
Not above medium size. Calyx subovoid; the sides uniformly curving 
| from the column to the arm bases; the ventral disk almost flat. Surface of 
| Bei | plates devoid of ornamentation or other markings, except a faint longitu- 
dinal angularity along the middle of the radials. 
a ie 
cee delieneaii adeeb seen Bale 
ee 
—> 
Nt nar 
— 
