412 PALEONTOLOGY OF ILLINOIS. 



ocrinm, with which the species agrees ill having only two radial pieces 

 to each ray. 



Specifically it is related to such forms as Cyatliocr'tnus macropleurus, 

 Hall, and Poteriocrmtts obuncu-s, White ; but it differs too widely from 

 these and all other similar forms known to us to render a comparison 

 necessary. Cyathocrinm macropleurus was described from a specimen 

 uot showing either the anal pieces or second radials, or the arms. Mr. 

 WACIISMTJTH has specimens, however, showing that it has several anal 

 pieces, and two radials to each ray. He also has specimens of the P. 

 obuncus (which was also described from a specimen not showing the 

 arms and second radials), indicating that it agrees in these characters 

 with Scapliiocrinm. It is possible such species should form a separate 

 section or subordinate group. 



Locality and position Lower division of the Burlington group, Bur- 

 lington, Iowa. Lower Carboniferous. No. 303 of Mr. WACHSMUTH'S 

 collection. 



SCAPHIOCRINUS RUDIS, M. and W. 



PI. 1, Fig. 1. 

 Scaphiocrinus rudis, MEEK and WORTHEX. Proceed. Acad. STat. Sci., Phila., 1869, p. 139. 



BODY much depressed, about four times as wide as high, 

 flat or a little concave below, the flattened part including 

 the basal, subradial, and about half the length of the first 

 radial pieces. Base very small, a little impressed, and en- 

 tirely hidden by the column. Subradial pieces of moderate 

 size, extending out horizontally from the column ; the one 

 on the anal side, however, curving up distinctly, and the 

 others slightly, at the ends; all flat, excepting the curva- 

 ture mentioned, and pentagonal in outline (the superior 

 angle being rather salient), excepting the one on the anal 

 side, which is hexagonal, being truncated above for the re- 

 ception of the anal piece. First radial pieces three or four 

 times as large as the subradials, twice as wide as long, very 

 tumid in the middle, and pentagonal in form, the lateral 

 margins being longer than the inferior, and the superior 

 one straight, and equaling the entire breadth. Second ra- 

 dial pieces of about the same size as the first, which they 

 equal in breadth below, though they are a little longer, and 



