'.)<> PALEONTOLOGY OF ILLINOIS. 



and possibly a second division takes place in all the arms in 

 perfect individuals. Arms as far as can be seen, composed of 

 short quadrangular joints, about twice as wide as long. 



Column round, and composed of alternately thick and thinner 

 joints, the former slightly projecting. 



Position and locality: Niagara limestone, near Clifton, Wayne 

 county, Tennessee. 



Collection of A. H. VVorthen. 



GENUS AMPHORACRINUS. Austin. 

 AMPHOKACRINUS JEKSEYENSIS. (sp. nov.) 



PI. XIV, Figs. 8-8a. 



Calyx short, the radial series spreading laterally so as to form 

 a low shallow cup, more than three times as wide as the height 

 to the base of the arms. The basal plates project slightly below, 

 so as to form a rim around the columnar facet. 



The specimen in hand has an abnormal structure, the anterior 

 ray being obsolete. The right posterior and the left anterior 

 divisions of the calyx have the normal number of three radials 

 to each ray; while the left posterior and the right anterior 

 divisions have but two radials each, the second being as large 

 or larger than the first and supporting the first arm plates. 



Anal plates three, the first hexagonal, the second smaller and 

 quadrangular, resting upon the first, with two larger anals on 

 either side which rest partly on the lateral sides of the first 

 radials, and partly on the first anal plate. Above these four 

 anals, there are six "slightly protuberant plates arranged around 

 a small anal opening. 



In the normal divisions of the calyx there is a single large in- 

 ter radial plate. 



On the anterior side there are four plates rather larger than 

 the first four on the anal side, and arranged in the same 

 manner. 



Summit composed of numerous nodose plates, a massive one 

 crowning the summit, as in some species of Agaricocrimm. 



The specimen has six arms, one each to the posterior, and two 

 each to the antero-lateral rays. 



Position and locality: Kinderhook group, Jersey county. 



Collector, A. H. Wort hen. 



No. 2582 of the Illinois State Museum. 



