INDIANA PALEONTOLOGY. lOO. 



axillary plate, a third division occurring on each inner branch. From the 

 tubercle extends outward on each side to the center of each adjacent first 

 radial, and each first interradial a low, sharp ridge. 



The second primary radial plate is about as long as wide and hexagonal 

 and sends outward from its center a low, sharp ridge, to the first interradial 

 •on each side. 



The third primary radial is apparently pentagonal and axillary. Each of 

 the radials resting on the upper, sloping sides of the third primary radial, are 

 axillary, and the plate resting on the inner side of this second axillar}- plate is 

 also a bifurcating plate, the whole supporting above, around the periphery, 

 thirty arms, six to the ray. 



Above the third primary radial, the radial ridges become much stronger 

 and round instead of sharp or angular. 



The first interradial (of the four series) is seven sided and supports above 

 three smaller interradials. 



Above the latter are apparently two other plates in the ealyx. The first 

 anal interradial is in the first radial ring, and of the same size as the first 

 radials, seven-sided, supporting above three smaller plates.' 



Above these latter are five little plates, and still above these five very 

 small plates. 



Between the arm bases in the anal interradius are still other five little 

 plates. 



The interradial plates of the anal area have central tubercles, so also 

 have the plates in the other four interradial areas, the center of each first in- 

 terradial giving off six, low, sharp ridges to the contiguous plates. There is 

 apparently but one minute interaxillary plate to the ray. 



In the depressed triangles formed by the radial ridges and the low, sharp 

 interradial ridges are three small granular tubercles. 



The column is round and the canal small. 



The plates of the ventral disk are ornamented by small tubercles, most 

 numerous along the ambulacral ridges and about the anal opening. 



The central dome plate has a larger wart-like tubercle. On each ambulac- 

 ral ridge, just over the arm openings is a long slender spine, directed a little 

 obliquely outward. 



The body is deeply lobed at the arm bases. 



The arm openings are directed a little upward. 



The anal opening is located laterally, as in Aorocrinus, and on a warty 

 prominence. 



Nothing is known of the arms or pinules of this species. 



