51) 



pair of arms. They are elongated and are close to the ambu- 

 lacral canals, and not through the vault itself as in some species. 



This species, when compared with D. corporosus, will be 

 found to have only a single tertiary radial, while in that 

 species there are four, and only two interradials, while in that 

 species there are from three to six plates, and the azygous 

 area is altogether different. There are also some minor differ- 

 ences in surface ornamentation and otherwise. There is no 

 necessity for comparing it with any other known species. 



Found by Geo. K. Greene, in the Hamilton Group, near 

 Charlestown,' Indiana, and now in the collection of Wm. F. E. 

 Gurley. 



DOLATOCRINUS SALEBROSUS, n. Sp. 



Plate III, Fig. 13, basal view; Fig. 14, side view; Fig. 15, 



summit view. 



Species medium or below medium size. Calyx subhemi- 

 spherical, concave below and slightly constricted below the 

 arms. Radial ridges consisting of small, rounded elevations 

 which are interrupted by central nodes on the plates. Surface 

 ornamented with radiating ridges from the nodes and central 

 part of the plates. The second interradials have a transverse 

 central ridge with longitudinal ridges below it. Column round 

 medium size, and nearly filling the funnel-shaped cavity formed 

 by the basal plates. 



Basal plates form a cup that is inserted into the cavity of 

 the calyx and is nearly tilled by the end of the column. The 

 mouth of the cup is about one-fourth wider than the diameter 

 of the column. First primary radials about as long as wide 

 and curve, at the lower end, into the basal concavity to unite 

 with the basal plates, and upward at the superior end, so that 

 the calyx will rest upon the middle part of these plates. Sec- 

 ond primary radials from one -fourth to one- half wider than 

 high, quadrangular, and slightly expanding upward. Third 

 primary radials a little larger than the second, about one-half 

 Wider than high, three hexagonal, two pentagonal, axillary, 

 and, in two of the rays, bear upon each upper sloping side a 

 single secondary radial which is axillary and bears upon each 

 superior side two tertiary radials, which gives to each of these 

 rays four arms. In each of two other rays, the third primary 



