550 PALAEONTOLOGY OF ILLINOIS. 



STJB-GEXUS SCAPHIOCKLNUS. 

 SCAPHIOCRINUS BAYENSIS, M. and W. 



PI. 20, Fig. 2. 



Poteriocrinitg (Scaphiocrimw) Bayensis, MEEK aud WOIITHEN, 1865. Proceed. Acad. Nat. Sci., Phila., 

 p. 157. 



BODY of medium size, rather depressed obconic below 

 the top of the first radials. Base about twice as wide as 

 high, expanding directly from the head of the column 011 

 a line with the subradial and first radial pieces. Basal 

 pieces moderately developed, wider than long, pentagonal, 

 and showing the whole surface of each in a side view. 

 Subradials about three times as large as the basal pieces, 

 somewhat wider than long, three hexagonal, and two on 

 the anal side apparently heptagonal, the angle at the mid- 

 dle of the under side being very obtuse. First radial pieces 

 wider, and a little shorter, than the subradials, all pen- 

 tagonal, apparently all transversely truncated their entire 

 breadth above. Second radials of nearly the same size as 

 the first, and like them pentagonal, but having the middle 

 angle above, and more salient, while the two superior 

 sloping sides each supports an arm, thus giving origin to 

 two arms to each ray, so far as seen, all of which are nearly 

 in contact all around below, excepting on the anal side. 



First anal piece smaller than the subradials, hexagonal 

 in form, and resting between the upper sloping sides of 

 two of the subradials, with its upper right edge supporting 

 one side of one of the first radials, and its left connecting 

 apparently with a second anal piece, the form of which 

 cannot be made out in the specimens seen. In the third 

 range one piece evidently rested upon the upper truncated 

 edge of the first anal piece, but its form and connection 

 with the other pieces on the left have not been determined. 



Arms long, and, as far as known, apparently simple 

 after the first division of each ray on the second radial 



