PLATYCRINID 2. 705 
Platycrinus verrucosus Wurtz. 
Plate LX VI. Figs. 8a, b, and Plate LX VIII, Figs. 1a, 6, ¢, d. 
1862. Wutte; Boston Journ. Nat. Hist., Vol. VIL, p. 502. 
Of medium size. Calyx below the arms deeply cup-shaped, about as 
wide as high; the sides almost straight, and the suture lines not grooved. 
Surface of the cup marked by somewhat scattered, very prominent, wart- 
like nodes, elevated abruptly. They are irregularly distributed, except upon 
the basals, where a row of ten large elongate nodes surround the column 
facet, their sharper ends pointing to the.column, the thicker and wider ends’ 
directed outward ; these are enclosed by an irregular row of somewhat 
smaller, rounded nodes. Surface of the arms not ornamented. 
Basal cup large, saucer-shaped, pentangular in outline, the angles point- 
ing upward ; flat at the bottom, the column facet circular, moderately large 
and but slightly depressed ; the interbasal suture lines indeterminable. Ra- 
dials sometimes a little longer than wide, the lateral faces straight and nearly 
parallel, the lower faces convex, the upper faces at the sides of the facet 
short and but slightly sloping. Radial facets less than half the width of 
the plates, and occupying but a small portion of their length. Costals small, 
trigonal. Distichals of the same ray in contact laterally; the first very 
small, the second somewhat larger. Palmars larger than the distichals. 
Arms four to six to the ray; smooth, rather long, moderately heavy at 
the proximal end, but tapering slightly upward. They are composed of 
rather long pieces, which become biserial above the third plate. Pinnules 
long. Structure of the ventral disk and column unknown. | 
Horizon and Locality. — Lower Burlington limestone, Burlington, Iowa. 
Type in the Museum of Comparative Zodlogy. | 
