290 PALAEONTOLOGY OF ILLINOIS. 



POTERIOCBINUS VARSOYiENSis, Wortben. 



PI. XXVIII, Fig. 15. 



Poteriocrinus Varsoviensis, WOKTHEN, Feb. 1882. 



Bulletin No. 1, of the Illinois State Museum of Natural History, p. 19. 



Body below tbe medium size, basin-shaped, a little more than 

 twice as wide as high to the top of the radial series. 



Base depressed, the basal plates and the lower angles of the sub- 

 radials forming the basal depression. 



Subradials on the anterior side hexagonal, sharply angular above 

 and extending up about half the length of the radial plates. 



Eadials pentagonal, wider than high, the articulating scar occu- 

 pying the entire width of the plate, with a well-defined suture be- 

 tween the radial and brachial series. 



Brachials, two to the ray on the anterior side, the first quadran- 

 gular and the second pentagonal, sharply angular above, and sup- 

 porting on their sloping sides the first divisions of the rays. On two 

 of the rays the arms bifurcate again on the sixth plate above the 

 brachial series, beyond which they are unknown. All the plates of 

 the body are finely rugose. Anal series unknown. 



Column slightly pentagonal where it joins the body, and composed 

 of alternate thin and thicker joints, but below more massive joints 

 are intercalated at short intervals. 



Geological position and locality: Warsaw beds of the St. Louis 

 group, Warsaw, Illinois. 



No. 2,458, Illinois State collection. 



POTERIOCRINUS SPINOBRACHIATUS, Worthen. 

 PI. xxix, Fie. i. 



Poteriocrinus spinolrachiatus, WOBTHEN. February, 1882. 



Bulletin No. 1, of the Illinois State Museum of Natural History, p. 20. 



Body of medium size, basin-shaped, about twice as wide as high 

 to the top of the radial series. Base slightly depressed, the under 

 basals small and concealed by the first columnar joints. 



Subradials about as wide as high, the lower angles curved inward, 

 forming a part of the basal concavity. 



Eadials about one-fourth wider than long, pentagonal, the upper 

 margins concave, leaving a gaping suture between them and the 

 brachial plates. 



