328 SMITHSONIAN INSTITUTION 



The Species of Waciismuthicrinus 

 I. Ramules small. 



BB very small, entirely covered by column. 



No iBr. 



Surface finely pustulose IV. spinosulus. 



BB extending beyond column. 

 iBr present or absent. 

 Surface smooth. 



Rays longitudinally angular. 



Small nodes on RR and axillaries ; iBr one or two. 



Ramules at intervals of 5 to 3 W . thiemei. 



Large spines, chiefly on axillary IBr. 

 iBr 1 to 4 or more. 



Ramules at intervals of 3 to 2 W . spinifer. 



Rays rounded. Specimens very large. 

 Very small nodes on axillaries. 

 iBr and illBr numerous. 



Ramules at intervals of 2 to 1 W. bernhardinae. 



Rays widely divergent. 



iBr numerous, first very large. 



Ramules at intervals of 3 to 2 W. iowensis. 



II. Ramules very large. 



iBr well-developed. 



Rays abutting above them W. ponderosus. 



Wachsmuthicrinus spinosulus (Miller and Gurley) 

 Plate XLIII, figs. 11-16 



Ichthyocrinus spinosulus Miller and Gurley, Bull. 5, Illinois St. Mus., 1894, P- 44> pi- 5, fig. 4- 



Attaining a large size. Crown elongate, in mature specimens spreading 

 upward almost to the level of infolding, where height to width is about 1.25 

 to 1 ; spread of calyx from column to IAx, 1 to 2. Base concave, with radials 

 projecting downward from the rim, often in strong nodes. Cross-section quin- 

 quelobate, side outline nearly straight. Rays rounded or slightly angular, in 

 some specimens marked by prominent nodes and strong transverse ridges on 

 lower brachials and axillaries, in others nearly smooth and simply convex ; rami 

 heavy, equal. Crown of mature specimen, 50 mm. high by 40 mm. wide; base 

 at outside of concavity, 15 mm.; column, 12 mm. 



IBB and BB completely covered by column, the former apparently resorbed 

 in one imperfect specimen. R and IBr widening regularly upward, IIBr 3. 

 Rays interlocking in typical specimens as high as the last IIBr; in some diverg- 

 ing immediately above IBri or IIBn. No regular interbrachials in the spaces 

 thus formed, and no room for any touching radials. Ramules small, com- 

 mencing on third to fifth IIIBr, and continuing usually on every third brachial 

 to the number of 8 to 10 before infolding; exceptionally at intervals of 6 or 7 

 brachials. Column large, expanding next to calyx. 



