108 
Kirtley F. Mather 
Delocrinus sp. 
Plate III, figures 1-lb. 
A third species of Delocrinus, larger than either of the two 
described above, is represented by a portion of the dorsal cup 
consisting of three basal and two radial plates. The shape of 
the cup and the funnel-like concavity of the base are similar 
to those of D. clubius. The basals are pentagonal, longer than 
wide, strongly convex longitudinally and gently concave later- 
ally; radiafs pentagonal, much wider than long, their surfaces 
sharply deflected along a line situated at the mid-length so that 
the upper portion of the plates is at approximately right angles 
to the lower portion; the anal side of the cup is missing. The 
surface of both basal and radial plates is coarsely pustulose 
and bears numerous, irregularly scattered, moderately large, 
tumid nodes, which are not present above the line of deflection 
of the radials; in addition there are indications that the basals, 
whose surface is deeply eroded in the material at hand, were 
ornamented by a single, large, sub-central spine or node. The 
speciflc relations of the specimen are not apparent. 
Horizon and locality. Morrow formation: near Ft. Gibson, 
Oklahoma (Station 301). 
Genus STEREOBRACHICRINUS n. gen. 
Crinoids with inflexible uniserial arms, the plates of which 
are solidly united by Arm sutures so that no motion of the arms 
above the attachment to the radials is possible. Ambulacral 
groove narrow, about as deep as wide; nerve canal situated 
near the center of the arm. 
This genus is based upon a half dozen specimens consisting 
of more or less complete, isolated arms. The dorsal cup is un- 
known and the reference to the Poteriocrinidae is provisional. 
No evidence that the arms were pinnulate has been observed. 
Genotype : 
Stereobrachicrinus pustullosus n. sp. 
Plate III, figures 9, 9a, 
Description. Arms uniserial, inflexible, sub-trigonal to sub- 
circular in cross-section, tapering gradually toward either end, 
very gently curved so that the ambulacral side is concave longi- 
