Descriptions of Xeic Geneva and Species of Fossils. 17 



out, rounded, rather slender, and composed of elongate, somewhat 

 wedge-shiiped joints; from which proceed strong, jointed pinnies, from 

 near the upper mai'gin of tlieir longer sides. These arm plates arc 

 much enlarged at the origin of the pinnies which are alternate on the 

 opposite sides of the arm, giving the I'a^'s a peculiarly' roughened as- 

 pect and tortuous direction. The pinules appear first on the third 

 and tiien on the sixth piece of the secondary- radials, above which 

 each succeeding plate is provided with one. In some specimens each 

 second or third piece, above the sixth plate of the secondar}- radial 

 series, appears to be divided into two; in that case the lower and small- 

 er piece is without a pinule. 



The first azygos inter-radial, or anal piece, is w^edge-shaped, with its 

 base resting upon the superior lateral sloping side of the second radial 

 of the right posterior ra}'. Above this there is a direct vertical range of 

 pieces, much rounded on the outer side, and reaching nearly to the ex- 

 tremities of the arms. The ventral prolongation is formed b}' thin ex- 

 tensions of these pieces, which proceed from their sides. The width of 

 these extensions is about one-sixteenth of an inch, more or less. 



Column of medium size, round, tapering downward from the calj^x. 

 near which, and to one and a half inches below the same, it is com- 

 posed of alternately thicker and thinner disks, the thicker ones 

 being slightly prominent at the edges; the rest of the column, as far as 

 observed, is nearly smooth, and composed of rather thin, sub equal 

 disks. 



The peculiarl}' roughened and tortuous rays of this species, which in 

 that respect remind one strongly of a number of sub-carboniferous 

 species of Poterioo'inus and Sccqjhiocrinas, will serve to distinguish 

 it from all the other species of the genus known to the writer. //. lax- 

 us, Hall, has this peculiarity developed in a small degree. Otherwise 

 it differs from this species in having a proportionally longer and more 

 angular bod}^ and shorter arm pieces; while the armlets or pinules are 

 proportionally stouter, much shorter, and are given off at longer inter- 

 vals. The column and calyx of IT. simplex, var. grandis, Meek, are 

 much like those parts in this species, but the very different structure 

 of the arms in- the two forms, and the difierent outlines of the third and 

 fourth primary' radials, and the absence of a ventral prolongation in 

 H. simplex^ clearly show that they are distinct. 



Formation and locality: the specimens used in the description were 

 found in the Utica shale, at Cincinnati, O., within fifteen feet of 

 low water mark in the Ohio River. 



Collected by J. G. Fine, S. A. Miller, E. O. Ulrich. 



