Fauna of the Morrow Group 
107 
angle, each plate bearing a single, massive, sub-centrally situ- 
ated, horn-shaped node protruding outward and curving later- 
ally from just within the flattened basal portion of the cup; 
radials pentagonal, broader than high, comparatively thick and 
massive, strongly convex longitudinally, more gently convex 
laterally, central portion thickened and tumid, upper surface 
truncated and faceted for attachment of primibrachs ; anal plate 
small, quadrilateral, resting upon the truncated edge of the pos- 
terior basal between the posterior radials ; body cavity shallow, 
cylindrical; arms and ventral disc unknown. 
Fig. 3. Diagram of dorsal cup of Delocrinus pentanodus. 
The dimensions of the holotype are : outside diameter of dorsal 
cup, 8.8 mm. ; height of dorsal cup, 2.5 mm. ; diameter of body 
cavity, 4.4 mm.; depth of body cavity, 1.7 mm. 
Remarks, Only one other species of this genus, D. nodu- 
liferous (Butts), described from the Upper Coal Measures at 
Kansas City, Missouri, is characterized by the presence of nodes 
on the plates of the dorsal cup. From that species the one here 
described may be distinguished by the larger size of the infra- 
basals relative to the diameter of the stem, the pentagonal form 
of the radials, and the absence of nodes or spines on the radials. 
Horizon and locality. Morrow formation: near Ft. Gibson, 
Oklahoma (Station 301). 
