24 



on each side at the base of the arms and a lurj^e oue that unites 

 with two plates in the interradial depression on the vault. There 

 seem to be no intersecondary radials. There is no azygous area. 



The vault is only slightly convex and moderately depressed in 

 the interradial areas. It bears a long subcental proboscis. It is 

 covered with large polygonal plates that are densely covered with 

 tubercles and short spines. The tubercles are not shown in the 

 illustrations because there are from twenty to fifty on each plate. 

 The two interradial plates in each area that abut upon the last 

 interradial in the calyx are elongated, and the larger plates of the 

 vault. There are no pores or passages that penetrate the vault 

 between the arms. 



The hemispherical form and peculiar surface ornamentation dis- 

 tinguish this species. Beside, the number of arms is different 

 from all related species. The number of plates and general order 

 of their arrangement in the calyx, however, are like those in D. 

 orncdus and D. bulbacevs, notwithstanding the wide variation in 

 the forms of the three species. 



Found in the Hamilton Group, at Charleston, Indiana, and. now 

 in the collection of Wm. F. E. Gurley. 



DOLATOCRINUS ADREATUS n. Sp. 



Plaie III, Fig. 1, hosal vieio; Fig. i, side view; Fig. H, siinniiH 



view. 



Calyx hemispherical. Surface ornamented with radiating ridges, 

 usually broken, and nodes; radial ridges sharp and more or less 

 interrupted at the sutures. The sculpturing is more dense than 

 shown in the illustrations. Column round. 



Basal plates display a pentagonal rim around the column, where 

 it enters the concavity formed by the basal plates. First primary 

 radials wider than long nnd abut upon the basal plates without 

 entering the columnar cavity. Second primary radials about twice 

 as wide as long, quadrangular, sides nearly parallel. Third pri- 

 mary radials about half as long as wide, pentagonal, expanding to 

 the lateral angles, and except three, supporting upon each of the 

 upper sloping sides a single secondary radial; three of them bear 

 three secondary radials each. 



Seven of the secondary radials bear upon each upper sloi)iug 

 side two tertiary radials, the last one of which is followed by the 



