PLATTCEmiD^. i^Q5 



Platyerinus verrucosus White. 

 Plate LXVI. Figs. 3a, h, and Plate LXVIIL Figs, la, h, c, d. 



1862. White ; Bostou Journ. Nat. Hist., Tol. VII., 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. Ea- 

 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 occuiDying but a small portion of their length. Costals small, 

 trigonal. Distichals of the same ray in con-tact 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. 



Rorizon and Locality/. — Lovrer Burlington limestone, Burlington, Iowa. 

 T//j)e in the Museum of Comparative Zoology. 



89 



