41 



gaping suture, but immediately within, a straight ridge extends 

 from one outer angle to the other having a furrow on each side 

 so as to form a hinge on which the second plates articulate; 

 behind this hinge in the middle part of each plate, there is 

 a socket for the reception of a tooth-like projection. Second 

 radials short and heavy and produced externally in a moder- 

 ately strong spine. 



First azygous plate longer than wide, pentagonal, upper side 

 short, abutting below on a subradial and resting ^ery slightly 

 oblique between another subradial and the under sloping side 

 of the first radial on the right. Second azygous plate longer 

 than wide, truncates a subradial, abuts upon the superior 

 lateral side of the first radial on the left, and the first and third 

 azygous plates on the right. Third azygous plates longer than 

 wide, truncates the first azygous plate, and abuts upon the 

 superior lateral side of the first radiaA on the right. The second 

 and third azygous plates are hexagonal, but the plates abut- 

 ting the superior side are not preserved in our specimens. A 

 small part of a proboscis is preserved in one of our specimens, 

 that shows some heavy, transversely furrowed plates. Other 

 parts not preserved. 



This species is so different from any other referred to this 

 genus, that no comparison will serve further to distinguish it. 

 There is a possibility that it is a Zeacrinus, but we think it is 

 not. 



Found in the Upper Coal Measures, at Kansas City, Missouri, 

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



HYDREIONOCRINTJS NODULIFERUS, n. ^p. 



Plate VI, Fig. 15, view opposite the azygous area; Fig. 16, 

 azygous view of the same specimen; Fig. 17, basal 

 view of the same, showing the protruding 

 part of the second radials. 



Calyx bowl- shaped, twice as wide as high; columnar cavity 

 abrupt; plate gently convex; sutures slightly beveled; surface 

 granular. Column round. 



Basals sunken in the columnar cavity and cnly slightly larger 

 than the diameter of the column. Subradials of moderate size 

 -6 G. 



