INDIANA PALEONTOLOGY. 108. 



It differs in the possession of five ambulacral spines quite as strong as the 

 central dome spine and a more convex ventral disk. The dorsal cup is very 

 little deeper and slightly more inflated, while the ambulacral ridges on the 

 ventral disk are a little better pronounced, the whole tegmen having somewhat 

 the appearance of a low, broad pentagonal pyramid. The central spine is di- 

 rected a little backward and the five ambulacral spines slightly outward. 



Horizon, collection and locality same as the last. 



GENN.EOCRINUS KENT UCKIEN SIS? Shumard ? Rowley. 



Plate 33. Figs. 10, 11, 12. 



This specimen seems to agree quite well with the species to which it is 

 above referred, save that it has but thirty arms, while Wachsmuth and Springer 

 state that Shumard' s species has forty. We suspect the authors were in error 

 as to the number. 



This is the largest form wg have yet seen. The dorsal cup is moderately 

 inflated and the basal plates form a low tripartite rim, but the first radials want 

 the strong node so conspicuous on the other species described in this series of 

 papers. The radial ridge is less strong, but the radiating lines from the plate 

 centers are sharply defined and numerous. The plates of the upper part of the 

 anal interrdius are provided with short spine-like central nodes, while all of 

 the ambulacral plates are similarly surmounted, giving the ventral disk a de- 

 cidedly burr-like aspect. The interambulacral plates are less spinose and 

 those around the anal opening are hardly more than smooth. There is no cen- 

 tral spine, and from the condition of preservation of the specimen, the presence 

 or absence of a strong spine at the ambulacral fork is a matter of conjecture. 

 The ventral disk is hardly convex and the arm lobes are quite strong. 



Upper Devonian beds. Falls of the Ohio. Collection of Mr. G. K. Greene. 



AOROCRINUS CASSEDAYI, Lyon, Rowley. 



Plate 33. Figs. 13, 14, 15. 



The specimen before us seems to be the form figured by Wachsmuth and 

 Springer in the Revision of the Palteocrinoidea as ,1. rassedayL differing from 

 the usual form in its greater width of body and almost flat ventral disk. 



Upper Devonian, near Charlestown, Ind. Collection of G. K. Greene. 



