508 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
Agaricocrinus stellatus Hatt. 
Plate XXXVUI. Figs. Va-e. 
1858. Han; Geol. Rep. Iowa, Vol. I., Part IL, p. 564. 
1881. W. and Sp.; Revision Paleocr., Part II., p. 113. 
Syn, Agaricocrinus geometricus Hatt ; 1860, Suppl. Geol. Rep. Iowa, p- 56. 
A small species, resembling A. dellatrema in the form of the dorsal cup, 
and A. bullatus in the construction of the tegmen. Calyx subpyramidal, 
wider than high, and distinctly pentangular across the arm facets, the sides 
a little constricted. Lower face of the dorsal cup somewhat convex, the 
basals and radials a little concave, or the radials stretched out horizontally 
and only the basals depressed. Plates flat, with shallow grooves along the 
suture lines. 
Basals sometimes extending beyond the column. Radials about as wide as 
long, the upper face twice as wide as the lower. First costals a little smaller 
than the radials, quadrangular, wider than long, and the upper face wider 
than the lower. Second costals pentangular, exceptionally hexangular or hep- 
tangular, generally a little wider than the first. Distichals 2 x 2 in the calyx; 
the upper one followed by two series of free brachials. Arm facets large, 
directed horizontally or nearly so; those of the same ray forming an angle 
of 60°. Arms ten, stout, gradually tapering, and composed of rather long 
joints. Interbrachials one and two; the first rising generally to the top of 
the first distichals; the two of the second row, which are narrow and long, 
come to a level with the arm openings. First anal much longer than the 
radials, followed by two rows of three plates. The upper part of the anal 
area 1s composed of irregular pieces forming a well defined ridge, which 
near its upper end contains the anus. Posterior oral large and spinous, 
the four others and the radial dome plates highly convex; interambulacral 
pieces almost flat. 
Horizon and Locality.— Lower layers of the Upper Burlington limestone; 
Burlington, Lowa, and at several places in Illinois and Missouri. 
Lype in the (Worthen) Mlinois State collection, Springfield. 
Agaricocrinus convexus (Hatt) W. and Sp. 
Plate XXX VIIT. Figs. 1a, b. 
1860. <Ayaricocrinus pentagonus, var. converus — Hatt; Suppl. Geol. Rep. Iowa, p. 58. 
1861. Ayaricocrinus convexus— W. and Sv.; Revision Paleocr., Part II., p. 112. 
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