510 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



Agaricocrinus Coreyi (Lyou and Cass.). 

 Plate XXXIX. Figs, la, b. 



I860. Actimcrimis Coreyi— Lyon and Cassedat ; Amer. Jourii. Soi. (sec. ser.), VoL XXIK., p. 76. 



Syu. Agaricocriims Sprhii/eri — White, 1881 ; Eleventli Aim. Sep. Geol. aud Kat. Hist, of ludiana, 

 p. 363, Plate 40, Figs. 2, 3, i. 



Of more than medium size. Calyx a little .shorter than wide. Dorsal 

 cup rather high for the genus, but somewhat lower than the ventral disk, 

 saucer-shaped, truncated at the bottom, the sides convex. Plates elevated, 

 sometimes a little angular, their surface smooth; suture lines distinctly 

 grooved. 



Basals rather small ; on a level with the radials, and forming a hexagon, 

 which is almost completely hidden by the column. Eadials stretched out 

 horizontally, except the uppermost part which bends slightly upward ; they 

 are twice as large as both costals together, and one third wider than long ; 

 their upper faces excavated and broader than the width of the plate at the 

 bottom. Costals twice as wide as long, the first quadrangular, the second 

 pentangular and frequently smaller than the first. Distichals two in the 

 calyx, very short ; the first wedge-shaped ; the second linear, followed by 

 leaf-like cuneate pieces, which interlock from opposite sides. Arm facets 

 lunate, unufsually lai'ge and directed horizontally. Arms unknown, but ap- 

 parently very stout. First interbrachial large, generally longer than wide, 

 followed at the arm regions by two elongate pieces in the second row, 

 and these by seven to eight interambulacral plates. First anal jolate con- 

 siderably longer than the radials, and forming with the two succeeding ones 

 a vertical row ; second anal about one half the size of the first, the third very 

 much smaller. Both these plates rest between two interbrachial pieces, of 

 wliich those in the first row are very large, but those of the second quite 

 small. Ventral disk pyramidal, pentangular in outline, the plates convex. 

 Posterior oral conical, central in position, and three times as large as the 

 four others. Interambulacral plates rather numerous, about one fourth the 

 size of the smaller orals. The rays are surmounted by a large radial plate, 

 placed close to the lower margin of the disk. Anus excentric, directed ob- 

 liquely upward, and occupying the upper end of an elongate, distinctly 

 rounded area, composed of small, smooth, irregular pieces. 



Horhon and Locality. — Keokuk group ; Hardin and Allen Cos., Ky., and 

 Vermilion Co., Ind. 



Type in the Lyon collection. 



