558 PALEONTOLOGY OF ILLINOIS. 



contracts rapidly to the top of the first radials, giving it a 

 globular form. First radials wider than long, four pen- 

 tagonal and one hexagonal, all abruptly curving inward 

 towards the center. Anal plates four, the lower one large, 

 nearly quadrangular in outline, the second about half the 

 size of the first, the others quite small, and all pentagonal. 

 Arms and column unknown. 



Locality and position Chester division of the Lower Carboniferous, 

 Chester, Illinois. 



AGASSIZOCKINUS GIBBOSUS, Hall. 



PI. 21, Fig. 11. 

 Agassizocrinus gibbosus, HALL, 185S. Geol. of Iowa, Vol. I, p. 686, PL 25, Fig. 6. 



Locality and position Chester division of the Lower Carboniferous, 

 Chester, Illinois. 



AGASSIZOCRIKUS OHESTEEENSIS, Worthen Ms. 



PI. 21, Fig. 9. 



BODY ovoid, protuberant at the base, and constricted at 

 the base of the arms. Base solid, with no well defined 

 suture lines, but showing a faint trace of the point of at- 

 tachment for the column. Subradial plates large, nearly 

 flat on their external faces, four pentagonal and two hex- 

 agonal, nearly twice as high as wide, and curved slightly 

 inward at their upper extremities. First radials small, 

 pentagonal, about twice as wide as high, and curving in- 

 ward from their junction with the subradials. Anal plates 

 three, the lower one large, subquadrangular in outline with 

 the upper right hand corner truncated, the other two small 

 and pentagonal. 



In general form this species bears some resemblance to A. giubosa, of 

 Hall, from which it may be readily distinguished by its flattened sub- 

 radials. Arms and column unknown. 



Locality and position Chester Limestone, Chester, Illinois. 



