43 



resemblance to any species described, in that genus. The sum- 

 mit of the proboscis will determine whether it belongs to 

 Hydreionocrinus or Zeacrinus. 



Found in the Upper Coal Measures, at Kansas City, Mis- 

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



HYDREIONOCRINUS CRASSIDISCUS, n. Sp. 



Plate VI, fig. 18, basal view; Fig. 19, azygous side view of 



the calyx. 



Calyx discoid, slightly concave below, plates convex; sutures 

 distinct, surface granular. Column round. 



Basals form a pentagon one-third wider than the columnar 

 cicatrix, which is concave and radiately furrowed, for the sup- 

 port of the attaching column. Columnar canal very small. 

 Subradials directed horizontally, convex, of unequal size, the 

 one on the right of the azygous area being the larger and 

 wider one; each one is hexagonal. First radials twice as wide 

 as long, convex, sutures depressed, directed almost horizontally, 

 so as to give the calyx a height little if any more than the thick- 

 ness of the plates; separated, on the outer face, from the sec- 

 ond radials, by a gaping suture, but immediately within, a 

 straight ridge extends from one outer anscle to the other, hav- 

 ing a furrow on the outside and depression on the inside so as 

 to form a hinge on which the second radial plates articulate. 

 Second radials not preserved in our specimen. 



First azygous plate quadrangular, longer than wide, resting 

 between a subradial and the first radial on the left, and the 

 under sloping side of the first radial on the right. The lower 

 end does not reach the second subradial, as is usual in this 

 genus. Second azygous plate longer than wide, truncates the 

 first azygous plate, and separates the superior lateral sides of 

 the two adjoining first radials. The third azygous plate barely 

 touches a first radial. 



Other parts of this species unknown, but the calyx is so dif- 

 ferent from any other described species that no comparison is 

 necessary to distinguish it. 



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

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



