294 PALEONTOLOGY OF ILLINOIS. 



The first anal is rather smaller than the second, and rests be- 

 tween two of the subradials and against the right posterior radial, 

 and extends to the summit of that plate. The second radial rests 

 on the upper margin of the left posterior subradial, and the third, 

 which is smaller than the first, rests upon it, and extends up to 

 the middle of the brachial on the right. 



Column round, but only a few joints are attached to the specimen. 



This species is closely allied to Pot, (Scaph.) internodius of Hall, 

 but differs from that in the form of its radials, but more especially 

 in its long zigzag arms. 



Position and locality: Chester limestone, near Columbia, Monroe 

 county, 111. 



No. 2,438, Illinois State collection. 



POTERIOCKINUS CLYTis, Worthen. 



PL XXX, Fig. 10. 



Poteriocrinus clytis, WOETHEN, February, 1882. 



Bulletin No. 1, of the Illinois State Museum of Natural History, p. 16. 



Body small, obconical, length and breadth at the top of the radial 

 plates about equal. Base truncated, the basal plates forming by 

 themselves a low pentagonal cup. Subradials about as wide as 

 high. Eadials pentagonal, length and width apparently about equal, 

 and support on their upper margins a single series of long slender 

 arm plates, making but five arms to the entire animal. 



The first arm plates on the two rays that are shown in the speci- 

 men before me, are three or four times as long as wide, and above 

 these a series of ten or twelve shorter plates are preserved, all 

 rounded externally and generally longer than wide. The anal 

 plates are only partially preserved, but the form of the first can be 

 clearly seen. It is pentangular, and rests between two subradials, 

 and under the right posterior radial. Above this, part of a short 

 cylindrical ventral tube is preserved. Eemains of short delicate 

 pinnules can be seen, attached to the inner borders of some of the 

 arm plates. 



Column rather stout, thicker at its junction with the body than 

 below, and composed of short even joints that alternate with thicker 

 ones below. 



